In Rocky, some data is collected automatically and some data you must first opt in to collecting before you process your simulation. In addition, some data is always collected right from the start of the simulation, and some data waits to be collected until passing certain thresholds that you define.

Use the topics below to help you understand what, how, and when data is collected in Rocky.

WHAT WOULD YOU LIKE TO DO?

See Also:

COLLECTING DATA IN ROCKY

Rocky provides many options for calculating, collecting, and analyzing different kinds of data.

Since calculating data you do not want can slow down your processing, and retaining data you do not need can take up valuable storage space, Rocky requires you to opt-in (or turn on) certain kinds of data collection. It does this to help you maximize your computing power and storage space.

To help you better understand how and when data is calculated, use the table below and the topics that follow.

Table 1: Rocky data and statistics collection matrix

No matter how or when the data you want is collected, the resulting Properties (see also About Properties) can be visualized after processing in a view window and/or analyzed through a plot or histogram window. In addition, any resulting Curves (see also About Curves) can be analyzed through a plot or histogram window.

If you cannot see any of your simulation data and you know you have both collected it and have completed as much of the processing for which you want to have data, then you most likely have not yet created a view, plot, or histogram window by which to view and/or analyze the data or statistics you have collected.

Tip: Once your plot or histogram window is created (see also Graph Data within Rocky by Creating a Plot or Histogram), you can then modify the display to your liking (see also About Changing the Appearance of a Graph (Plot or Histogram)), export the data into a CSV file for further analysis outside of Rocky (see also Export Data into a CSV File), and more.

See Also:

MONITORING OVERLAPS

In Rocky versions prior to 2022 R1, there was a built-in contact overlap monitor whose purpose was to check each contact pair (particle-particle or particle-boundary) for the amount that they overlapped, the percentage of which was determined by the size of the smallest particle in the contact pair.

During simulation processing, if at any timestep a contact pair's overlap exceeded one of three warning levels fixed at 2.5%, 10%, and 20%, a Contacts overlap message would be raised on the Simulation Log panel (Figure 1). (See also I get warnings or errors on my Simulation Log Panel.)

Figure 2.166: Example Contacts overlap message on the Simulation Log panel

Monitoring your contacts for the size of their overlaps is important because Rocky is based on the soft-sphere approach, which uses the overlap value in order to compute collision forces. For example, in a typical simulation overlaps of 2.5% might be considered acceptable; however, simulations with overlaps larger than 10-20% should probably not be trusted as overlap values that large can lead to serious stability and accuracy issues.

Although it is a good practice to monitor overlap levels to guarantee they are below the desired values for a DEM solver, for some types of projects, the default warning levels Rocky uses might not be appropriate; or, it might be desired for there to be no overlap checks at all.

Therefore, as of Rocky 2022 R1, you are able to choose:

These tasks are accomplished via an embedded Module called Contacts Overlap Monitor (Figure 2).

  Figure 2: Options in the Data Editors panel for the Contacts Overlap Monitor Module

CONTACTS OVERLAP MONITOR OPTIONS

Use Figure 2 above and the table below to understand how to monitor your contact overlaps.

Table 1: Modules, Contacts Overlap Monitor parameter definitions

What would you like to do next?

TURN OFF THE OVERLAP MONITOR

The Contacts Overlap Monitor module is "on" (enabled) by default to match the behavior in older versions of Rocky.

Although it is a good practice to monitor overlap levels to guarantee they are below the desired values for a DEM solver, use the following procedure if you do not want to monitor contact overlaps in your simulation.

To Turn Off the Overlap Monitor:

See Also:

CHANGE THE OVERLAP MONITOR WARNING LEVELS

The initial values defined in the Contacts Overlap Monitor module are designed to match the warning levels used in older versions of Rocky. Use the following procedure if you want to define different warning thresholds for your contact overlaps.

Note: This process can only be completed prior to processing your simulation.

To Change the Warning Level Values used in the Overlap Monitor:

See Also:

COLLECTING DATA ON BOUNDARIES

In Rocky, some boundaries data is collected automatically and some data you must first opt in to collecting before you process your simulation. In addition, some boundaries data is always collected right from the start of the simulation, and some data waits to be collected until passing certain thresholds that you define.

Use the topics below to help you understand what, how, and when boundaries data is collected in Rocky.

COLLISION STATISTICS FOR BOUNDARIES

By default, Rocky automatically collects data about the surface, make-up, and movement of individual geometries and conveyors. However, if you want to analyze the effects of particles colliding with these boundaries (for example, to study collision frequency, intensities, impact velocities, and so on), you will need to turn on Boundary Collision Statistics collection prior to processing your simulation.

About Collecting Boundary Collision Statistics

If you want to analyze this type of information in your simulation, you must first enable its collection via its module prior to processing your simulation.

Because collecting collisions statistics can take more processing time, memory, and disk storage due to increased file sizes, Rocky enables you to select from one or more sub-categories of statistics to collect. These are made available through the Boundary Collisions Statistic Module (Figure 1).

Figure 2.167: Options in the Data Editors panel when the Boundary Collision Statistics Module is enabled

Tip: To maximize your processing capabilities, choose only the statistics that you require for your analyses.

During processing, Rocky collects the selected collision statistics between two consecutive output time levels for all boundaries in your project.

Tip: To view walk-through examples of collecting and analyzing boundary collisions statistics, refer to the following Tutorials:

About Analyzing Boundary Collision Statistics

Once the collisions data is collected (post-processing), specific collisions-related Properties (Figure 2) and Curves (Figure 3) will be available for the geometry or conveyor you select. (See also About Properties and About Curves.) The specific Properties and Curves available depends upon which statistics you enabled prior to processing.

Figure 2.168: Boundary Collision Properties available for geometries after processing

Tip: These properties will be categorized as Statistical in the Evaluation column. (See also About Viewing an Individual Statistic.)

Figure 2.169: Boundary Collision Curves available for geometries after processing

You can then choose to analyze the resulting Properties or Curves in a plot or histogram window. (See also Graphing (Plot or Histogram) a Data Set Within Rocky)

Or, you can then choose to display the Properties information graphically on the surface of your boundaries in a 3D View window. This can be useful, for example, for showing a color map of surface intensity (Figure 3). (See also View a Color Map of Wear on the Default Belt or Imported Geometry Itself.)

Figure 2.170: Color map of surface intensity

By using the Properties tab for the geometry, the options on the Coloring tab, and/or by using the slider on the Time toolbar (see also About the Time Toolbar), you can change how the data appears in the window. Tip: You may also limit your data further by using Time Statistics Properties. (See also About Adding and Editing Time Statistics Properties.)

Tip: Learn more by referring to the "Collision statistics" section in the DEM Technical Manual. (From the Rocky Help menu, point to Manuals, and then click DEM Technical Manual.)

Boundary Collision Statistics Collection Options

Use Figure 1 above and the table below to understand how to collect collision statistics for your boundaries.

Table 1: Modules, Boundary Collision Statistics parameter definitions

What would you like to do next?

Enable and View Collision Statistics for Boundaries

Analyzing collision statistics for boundaries (see also About Collision Statistics for Boundaries) involves turning on the collection of the collision properties you want prior to processing your simulation.

After processing, you are then able to analyze the resulting Properties and/or Curves as you normally would.

To Enable and View Collision Statistics for Boundaries:

See Also:

COLLECTING DATA ON PARTICLES

In Rocky, some Particles data is collected automatically and some data you must first opt in to collecting before you process your simulation. In addition, some Particles data is always collected right from the start of the simulation, and some data waits to be collected until passing certain thresholds that you define.

Use the topics below to help you understand what, how, and when Particles data is collected in Rocky.

ABOUT INTER-GROUP CCOLLISION STATISTICS

If you want to analyze the effects of collisions upon various particle-particle or particle-boundary pair groups within your simulation, you can choose to collect Inter-group Collision Statistics prior to processing your simulation.

About Collecting Inter-group Collision Statistics

Because collecting collisions statistics can take more processing time, memory, and disk storage due to increased file sizes, Rocky enables you to select from one or more sub-categories of statistics to collect. These are made available through the Inter-group Collision Statistics Module (Figure 1).

Figure 2.171: Options in the Data Editors panel when the Inter-group Collision Statistics Module is enabled

In addition, only particles and geometries belonging to particle groups and geometry components that have been enabled for Inter-group Collision Statistics collection will be recorded (Figures 2 and 3).

Figure 2.172: Additional module options for Particle groups when the Inter-group Collision Statistics module is enabled

Figure 2.173: Additional module options for a geometry component when the Inter-group Collision Statistics module is enabled

During processing, Rocky collects the selected collision statistics between two consecutive output time levels for each participating particle-particle and particle-boundary pair.

About Analyzing Inter-group Collision Statistics

Once the collisions data is collected (post-processing), specific collisions-related Curves (Figure 2) will be available for the main Particles entity. (See also About Curves.)

Figure 2.174: Curves for Particles (simulation-wide) when Inter-group Collision Statistics are enabled

You can then choose to analyze the resulting Curves in a time or cross plot window. (See also Graphing (Plot or Histogram) a Data Set Within Rocky.)

Inter-group Collision Statistics Collection Options

Use Figure 1 above and the table below to understand how to collect Inter-group Collision Statistics.

Table 1: Modules, Inter-group Collision Statistics parameter definitions

What would you like to do next?

See Also:

ABOUT INTRA-PARTICLE COLLISION STATISTICS

For certain solid and flexible Particle sets in Rocky (see Supported Particle Sets section below), you can choose to have collision data between two consecutive output time levels collected by Rocky during the simulation. In this version of Rocky, this is referred to as Intra-particle Collision Statistics.

About Collecting Intra-particle Collision Statistics

Because collecting collisions statistics can take more processing time, memory, and disk storage due to increased file sizes, Rocky enables you to select from one or more sub-categories of statistics to collect. These are made available through the Intra-particle Collision Statistics Module (Figure 1).

Figure 2.175: Options in the Data Editors panel when the Intra-particle Collision Statistics Module is enabled

During processing, Rocky collects the selected collision statistics between two consecutive output time levels for all applicable particle sets in your project.

Tip: To see a walk-through example of collecting and analyzing Intra-particle collisions statistics, refer to Tutorial - Tablet Coater in the Rocky Tutorial Guide.

Supported Particle Sets

This feature works only with Particle sets that have the following characteristics:

(See also About Adding and Editing Particle Sets.)

If you choose to enable Intra-particle Collision Statistics, then you must have at least one Particle set in your simulation that meets the above criteria. Otherwise, Rocky will not process the simulation, and you might see the following error:

Figure 2.176: Rocky error shown if no particle sets in the simulation support Intra-particle Collisions Statistics

If you see this error after attempting to process your simulation, either disable Intra-particle Collision Statistics, or add a particle set that supports this type of collection.

About Analyzing Intra-particle Collisions Statistics

Once the collisions data is collected (post-processing), specific collisions-related Properties (Figure 3) will be available for the supported particle set you select. (See also About Properties.) The specific Properties available depends upon which statistics you enabled prior to processing.

Figure 2.177: Particles Details window showing Stress Normal collision statistics for a particle set

You can then choose to display the collisions data graphically on the surface of a representative particle in the Particles Details window (Figure 3).

By using the slider on the Time toolbar (see also About the Time Toolbar), you can see how the data changes at different points in time.

About Collision Statistics Visualization

In the collision statistics visualization, a value displayed at a given vertex is representative of all collisions in the region of influence of the vertex that occurred in all enabled particles of the particle set being analyzed, during the time lapse between two output time levels. This means that data displayed at time is the result of the statistics of the collision that happened between time and , where is the output period.

As usual in these type of representations, values displayed at other, non-vertex points of the particle are obtained by interpolation of available values from the surrounding vertices.

In order to get a statistical value per particle, the collision statistics that happened during that output is divided by the number of enabled particles at the time when the statistics are displayed. Therefore, it is important that these statistics should be used only when you have reached a point during the simulation where the number of particles during that output is nearly constant.

Otherwise, for example, suppose you have 100 particles from the beginning of the output period to the middle of it, and at the last time step of the output period, you have only 1 particle. The statistics of all 100 particles that were there will be divided by 1 (the number of particles at the final time step of that output period), giving values much higher than expected.

Conversely, if you get these statistics at the beginning of your simulation and particles are entering, for example, you may have 0 particles at the beginning of the first output period and 1000 particles at the end. In this case, the collision statistics will be divided by 100 and will give values much smaller than expected.

Intra-particle Collision Statistics Collection Options

Use Figure 1 above, and the figure and table below to understand how to collect Intra-particle Collisions Statistics.

Table 1: Modules, Intra-particle Collisions Statistics parameter definitions

Figure 2.178: Particle | Modules sub-tab available when Enable per Group Statistics is selected

What would you like to do next?

ABOUT INTER-PARTICLE COLLISION STATISTICS

If you want to expand the set of particle properties available for post-processing, including several statistical properties that may be collected during a simulation, you can choose to collect Inter-particle Collision Statistics prior to processing your simulation.

These can be useful when you need to extract data considering all collisions that happened to a certain particle between two output periods. For example, with impact velocity, you could relate that data to the chances of the particle breaking or causing it to de-agglomerate. With duration, you could relate that data to a certain mass or heat transfer process, or to a certain chemical reaction.

About Collecting Inter-particle Collision Statistics

Because collecting collisions statistics can take more processing time, memory, and disk storage due to increased file sizes, Rocky enables you to select from one or more sub-categories of statistics to collect. These are made available through the Inter-particle Collision Statistics Module (Figure 1).

Figure 2.179: Options in the Data Editors panel when the Inter-particle Collision Statistics Module is enabled

During processing, Rocky collects the selected collision statistics between two consecutive output time levels for all particles in your project.

ABOUT ANALYZING INTER-PARTICLE COLLISION STATISTICS

Once the collisions data is collected (post-processing), specific collisions-related Properties (Figure 2) will be available for the main Particles entity. (See also About Properties.) The specific Properties available depends upon which statistics you enabled prior to processing.

Figure 2.180: Properties available for the main Particles entity when Inter-particle Collision Statistics is enabled

You can then choose to analyze the resulting Properties in a plot or histogram window. (See also Graphing (Plot or Histogram) a Data Set Within Rocky.)

Or, you can choose to display the Properties information in a 3D View window. (See also About 3D View Windows.)

By using the Properties tab for the main Particles entity, the options on the Coloring tab, and/or by using the slider on the Time toolbar (see also About the Time Toolbar), you can change how the data appears in the window.

Inter-particle Collision Statistics Collection Options

Use Figure 1 above and the table below to understand how to collect Inter-particle Collision Statistics.

Table 1: Modules, Inter-particle Collision Statistics parameter definitions

What would you like to do next?

ABOUT FLUID-RELATED STATISTICS FOR PARTICLES

For most CFD Coupling options where the fluid flow affects the motion of the particles (1-Way Constant, 1-Way Fluent, and 2-Way Fluent), you can choose to collect CFD Coupling Particle Statistics prior to processing your simulation.

These can be useful when you need to extract data considering the fluid effects upon a particle between two output periods.

About Collecting Fluid-Related Statistics for Particles

Because collecting statistics can take more processing time, memory, and disk storage due to increased file sizes, Rocky enables you to select from one or more sub-categories of statistics to collect. These are made available through the CFD Coupling Particle Statistics Module (Figure 1).

Figure 2.181: Options in the Data Editors panel when the CFD Coupling Particle Statistics Module is enabled

During processing, Rocky collects the selected fluid-related statistics between two consecutive output time levels for all particles in your project.

About Analyzing Fluid-Related Statistics for Particles

Once the data is collected (post-processing), specific fluid-related Properties (Figure 2) will be available for the main Particles entity. (See also About Properties.) The specific Properties available depend upon which statistics you enabled prior to processing.

  Figure 2: Properties available for the main Particles entity when CFD Coupling Particle Statistics is enabled

You can then choose to analyze the resulting Properties in a plot or histogram window. (See also Graphing (Plot or Histogram) a Data Set Within Rocky.)

Or, you can choose to display the Properties information in a 3D View window. (See also About 3D View Windows.)

By using the Properties tab for the main Particles entity, the options on the Coloring tab, and/or by using the slider on the Time toolbar (see also About the Time Toolbar), you can change how the data appears in the window.

CFD Coupling Particle Statistics Collection Options

Use Figure 1 above and the table below to understand how to collect Fluid-Related Statistics for Particles.

Table 1: Modules, CFD Coupling Particle Statistics parameter definitions

What would you like to do next?

ABOUT PARTICLE INSTANTANEOUS ENERGIES

If you want to perform global or partial energy balances in a simulation, you can choose to collect particle instantaneous energies prior to processing your simulation, which enables the calculation of the kinetic and potential energies of each individual particle in the simulation.

About Collecting Particle Instantaneous Energies

You choose to collect these kind of particle energies by enabling the Particle Instantaneous Energies Module (Figure 1).

Figure 2.182: There are no options in the Data Editors panel when the Particle Instantaneous Energies Module is enabled

During processing, Rocky collects particle energies data for each particle based upon its translational/rotational velocity and position in space.

About Analyzing Particle Instantaneous Energies

Once the energies data is collected (post-processing), specific energy-related Properties (Figure 2) and Curves (Figure 3) will be available for the main Particles entity. (See also About Properties and About Curves.)

Figure 2.183: Properties for Particles (simulation-wide) when Particle Instantaneous Energies is enabled

These Properties are based on the following energies calculations:

Figure 2.184: Curves for Particles (simulation-wide) when Particle Instantaneous Energies is enabled

The Energy Delta Curve represents a variation (delta) in total energy of the particles recorded during an interval between two consecutive output times.

You can choose to visualize the resulting Properties and Curves in a 3D View window (Figure 3), or analyze the results in a time or other plot window. (See also Graphing (Plot or Histogram) a Data Set Within Rocky.)

Figure 2.185: Energy : Potential property for Particles shown in a 3D View window

What would you like to do next?

See Also:

ENABLE AND VIEW INTER-GROUP COLLISION STATISTICS FOR PARTICLES

Analyzing Inter-group Collision Statistics for each particle-particle or particle-boundary pair group (see also About Inter-group Collision Statistics) involves turning on the collection of the collision properties you want prior to processing your simulation, and then determining which particle groups and geometries you want to involve in that collection.

After processing, you are then able to analyze the resulting Curves.

To Collect and View Inter-group Collision Statistics:

See Also:

ENABLE AND VIEW COLLISION STATISTICS FOR PARTICLE SURFACES (INTRA)

Analyzing collision statistics for particle surfaces involves first turning on the collection of Intra-particle Collision Statistics prior to processing the simulation (see also About Intra-Particle Collision Statistics), and then viewing the resulting Properties for a supported Particle set on the surface of a representative particle in a Particles Details window.

By using the slider on the Time toolbar (see also About the Time Toolbar), you can see how the data changes at different points in time.

To Collect and View Collision Statistics for Particle Surfaces (Intra:

Tips:

See Also:

ENABLE AND VIEW COLLISION STATISTICS FOR PARTICLES BETWEEN OTHER PARTOCLES (INTER)

Analyzing inter-particle collision statistics (see also About Inter-particle Collision Statistics) involves turning on the collection of the collision properties you want prior to processing your simulation.

After processing, you are then able to analyze the resulting Properties as you normally would.

To Collect and View Collision Statistics for Particles Between Other Particles (Inter:

See Also:

ENABLE AND VIEW INSTANTANEOUS ENERGIES FOR PARTICLES

Analyzing Particle Instantaneous Energies (see also About Particle Instantaneous Energies) involves turning on the collection of energies data prior to processing your simulation.

After processing, you are then able to analyze the resulting Properties as you normally would.

To Collect and View Inter-group Collision Statistics:

See Also:

ENABLE AND VIEW FLUID-RELATED STATISTICS FOR PARTICLES

Analyzing fluid-related statistics for particles (see also About Fluid-Related Statistics for Particles) involves turning on the collection of the fluid-related properties you want prior to processing your CFD Coupling simulation.

After processing, you are then able to analyze the resulting Properties for the main Particles entity as you normally would.

To Collect and View Fluid-Related Statistics for Particles

See Also:

COLLECTING DATA ON CONTACTS AND ENERGY SPECTRA

In Rocky, contacts and energy spectra data is collected only if you first opt in to collecting them before you process your simulation. After choosing to collect it, contacts data is always collected right from the start of the simulation. However, data for energy spectra waits to be collected until passing certain thresholds that you define.

TYPES OF ENERGY SPECTRA

Depending on the source of the energy values considered, two types of energy spectra plots are available in Rocky: Contacts Energy Spectra and Particles Energy Spectra.

Based upon your energy analysis needs, you can use either or both types of energy spectra in your simulation.

Use the topics below to help you understand what, how, and when contacts and energy spectra data is collected in Rocky.

ABOUT CONTACTS ENERGY SPECTRA

In Rocky, it is possible simulate the breakage behavior of particles. (See also Enable Particle Breakage Calculations.) However, simulations with breakage enabled can increase the computational cost, taking longer to process the simulation. With this in mind, Rocky has another feature you can use to analyze breakage: Contacts Energy Spectra.

This useful tool collects different kinds of energy statistics per contact pair (particle group and/or geometry) and size, which helps provide insight into the distribution of the energies of all collisions that occurred in a simulation up to a given time. In this version of Rocky, these statistics are collected through the Contacts Energy Spectra module (Figure 1).

Figure 2.186: Options in the Data Editors panel when the Contacts Energy Spectra Module is enabled

This kind of energy spectra is often used in conjunction with Particles Energy Spectra. (See also About Particles Energy Spectra.)

See the sections below for more information about this type of energy statistic, and how it is collected, calculated, and viewed in Rocky.

About Collecting Contact-Based Energy Statistics

For contact-based analysis, the energy statistics of particle collisions are collected per collision; i.e., every separate particle-to-particle or particle-to-geometry impact will have its resulting energy collision stored. Each statistics pair-which is composed of either two Particle sets or one Particle set and one Geometry-will present a separate Energy Spectra curve. In this version of Rocky, only particles and geometries belonging to particle groups and geometry components that have been enabled for energy spectra collection will be recorded (Figures 2 and 3).

Figure 2.187: Additional module options for Particle groups when the Contacts Energy Spectra module is enabled

Figure 2.188: Additional module options for a geometry component when the Contacts Energy Spectra module is enabled

These curves are based upon three different types of collision energy, each of which can be useful for different types of analyses: Dissipation Energy, Impact Energy, and Shear Energy.

Because collecting statistics can take more processing time, memory, and disk storage due to increased file sizes, Rocky enables you to select which of these three collision energies you want to collect, and enables you to choose which particle groups and geometry components will participate in energy spectra collection.

About Setting Time Delays

It is important to realize that data is only collected after both the Start Time and Time Delay After Release values are reached. Data begins being collected at the Start Time but only for the particles that were released before the Time Delay After Release value. This is to allow enough time for the particle flow within your simulation to reach a steady state before the energy spectra calculations begin.

For example, if the Start Time is 5s, and the Time Delay After Release is 3s, a particle entering the simulation at 4s will only be accounted for after 7s of simulation time.

Applications for Contacts Energy Analysis

One common application of this type of analysis is for comminution devices like SAG mills (Figure 4), which use steel balls or other kinds of grinding media to help break rock or ore material into smaller fragments.

Figure 2.189: SAG Mill Simulated with both Grinding Media (Steel Balls) and Ore (Rock)

Although mills have great energy consumption, only a small part of this energy is converted into actual particle fragmentation. This inefficiency is mainly due to the fact that not all impacts lead to breakage. Impacts of low energy will not cause breakage, while excessive intensity impacts apply only part of the total energy to the breakage process. The rest of this energy is lost.

Therefore, it is important to understand how power is consumed during comminution processes in order to improve grinding efficiency. The Contact-based analysis is especially useful when combined with the Cumulative Power analysis for a comminution process because you can get an estimate of how collision energy is distributed amongst contacts.

In this way, by comparing contacts energy spectra per material pair for different equipment designs, higher collision energies involving the material to be broken (rock-rock, rock-ball, or rock-wall, for example) might lead to higher particle breakage. On the other hand, collision energies involving only the equipment or grinding materials (ball-ball or ball-wall, for example) could be considered wasted by not leading to particle breakage, and should be minimized through improved designs.

Contacts Energy Spectra curves can be displayed by Power, Cumulative Power (Figure 5), and Rate.

Figure 2.190: Examples of Contacts Impact Energy Spectra curves for various particle-to-particle and particle-to-geometry contact pairs

Viewing Contacts Energy Spectra

If prior to processing your simulation, you enabled Contacts Energy Spectra to be collected, then while the simulation is processing, Rocky calculates the selected energy curves (Dissipation, Impact, and/or Shear) for each pair of particle-to-particle or particle-to-geometry contact types, each generated by the power, cumulative power, and collisions rate (Figure 6).

Figure 2.191: Curves tab for Particles showing three sections for Energy

You can then create a Cross plot of the Curves you are interested in analyzing (Figure 7).

Figure 2.192: Example cross plot of Contacts Energy Spectra showing both Cumulative Power and Power, for impact collisions between particles and geometries

About Opening Older Energy Spectra Projects

When opening projects that were created and processed in versions of Rocky prior to 2022 R1, Rocky will still read the energy spectra data in those projects and will display the energy spectra Curves as usual.

However, if you want to modify and then re-process an older energy spectra simulation in 2022 R1 or later versions, you will need to enable the energy spectra modules and define the type of collection parameters you want prior to processing the simulation.

The same is true for projects that you have created but not processed in older versions of Rocky; you must enable and define the energy spectra modules manually before processing your simulation.

Contacts Energy Spectra Collection Options

Use Figures 1-3 above and the tables below to understand how to collect contact-based energy statistics.

Table 1: Modules, Contacts Energy Spectra parameter definitions

Table 2: Individual Geometry, Modules sub-tab parameter definitions

Table 3: Individual Particle Group, Modules sub-tab parameter definitions

What would you like to do?

See Also

ABOUT PARTICLES ENERGY SPECTRA

In Rocky, it is possible simulate the breakage behavior of particles. (See also Enable Particle Breakage Calculations.) However, simulations with breakage enabled can increase the computational cost, taking longer to process the simulation. With this in mind, Rocky has another feature you can use to analyze breakage: Particles Energy Spectra.

This useful tool collects different kinds of energy statistics per particle type and size category defined in its PSD, which can help predict breakage and attrition rates for continuous processes such as grinding mills. In this version of Rocky, these statistics are collected through the Particles Energy Spectra module (Figure 1).

Figure 2.193: Options in the Data Editors panel when the Particles Energy Spectra Module is enabled

This kind of energy spectra is often used in conjunction with Contacts Energy Spectra. (See also About Contacts Energy Spectra.)

See the sections below for more information about this type of energy statistic, and how it is collected, calculated, and viewed in Rocky.

About Collecting Particles-Based Energy Statistics

For particle-based analysis, relevant energy values associated to the collisions experienced by each individual particle collected during the simulation. In this version of Rocky, only particles belonging to particle groups that have been enabled for energy spectra collection will be recorded (Figure 2).

Figure 2.194: Additional module options for Particle groups when the Particles Energy Spectra module is enabled

Rocky then classifies and accumulates the associated specific energy values (energy per particle mass) according to a predefined set of energy levels, and represents the resulting cumulative values as curves.

For Particles Energy Spectra analysis, each particle group and particle size category will present a separate Energy Spectra curve. These curves are based upon three different types of collision energy, each of which can be useful for different types of analyses:

Because collecting statistics can take more processing time, memory, and disk storage due to increased file sizes, Rocky enables you to select which of these three particles energies you want to collect, and enables you to choose which particle groups will participate in energy spectra collection.

About Setting Time Delays

It is important to realize that data is only collected after both the Start Time and Time Delay After Release values are reached. Data begins being collected at the Start Time but only for the particles that were released before the Time Delay After Release value. This is to allow enough time for the particle flow within your simulation to reach a steady state before the energy spectra calculations begin.

For example, if the Start Time is 5s, and the Time Delay After Release is 3s, a particle entering the simulation at 4s will only be accounted for after 7s of simulation time.

Applications for Particles Energy Analysis

One common application of this type of analysis is for comminution devices like SAG mills (Figure 3), which use steel balls or other kinds of grinding media to help break rock or ore material into smaller fragments.

Figure 2.195: SAG Mill Simulated with both Grinding Media (Steel Balls) and Ore (Rock)

By looking at energy levels applied to particles, for instance, you can predict breakage rates.

Figure 2.196: Particles Energy Spectra curves related to Impact Energy

In the example shown in Figure 4 above, the Y-axis gives the Cumulative Specific Power : Impact values resulting from all collisions starting from the Start Time time you enter until the end of the simulated time (see also About Solver Parameters). The value of the Y-coordinate of a given point on the curve is obtained by dividing the cumulative specific energy by the time elapsed since the referred starting time. This value accounts for all collisions with a specific impact energy equal or higher than the specific energy given by its X-coordinate.

This kind of energy spectra curve is useful for the reason that all collisions with specific impact energy higher than a known threshold value may lead to particle breakage, while the remaining collisions will not, as shown in Figure 5 below. Therefore, the cumulative specific power available for breakage in that case will be given by the Y-coordinate in the curve, corresponding to the breakage threshold value.

Figure 2.197: Particles Energy Spectra comparison

Tips:

Viewing Particles Energy Spectra

If prior to processing your simulation, you enabled Particles Energy Spectra to be collected, then while the simulation is processing, Rocky calculates the selected Cumulative Specific Power curves (Dissipation, Impact, and/or Shear) for each particle set, generated by each size of the particle size distribution, and separated by Specific Energy. These curves are grouped under Specific Energy on the Curves tab (Figure 6).

Figure 2.198: Curves tab for Particles showing three sections for Specific Energy

Using these curves, you can then create a Cross plot, similar to the example below (Figure 7).

Figure 2.199: Example cross plot showing Specific Shear Energy Curves

About Opening Older Energy Spectra Projects

When opening projects that were created and processed in versions of Rocky prior to 2022 R2, Rocky will still read the energy spectra data in those projects and will display the energy spectra Curves as usual.

However, if you want to modify and then re-process an older energy spectra simulation in 2022 R2 or later versions, you will need to enable the energy spectra modules and define the type of collection parameters you want prior to processing the simulation.

The same is true for projects that you have created but not processed in older versions of Rocky; you must enable and define the energy spectra modules manually before processing your simulation.

Particles Energy Spectra Collection Options

Use Figures 1-2 above and the tables below to understand how to collect particle-based energy statistics.

Table 1: Modules, Particles Energy Spectra parameter definitions

Table 2: Individual Particle Group, Modules sub-tab parameter definitions

What would you like to do?

See Also

ENABLE AND VIEW DATA FOR CONTACTS ENERGY SPECTRA

Analyzing data for Contacts Energy Spectra involves first turning on the type of collection you want prior to processing the simulation (see also About Contacts Energy Spectra), and then determining which particle groups and geometries you want to involve in that collection. After processing your simulation you can then plot the resulting Curves (Figure 1).

Figure 2.200: Example cross plot showing energy spectra values

It is important to realize that data is only collected after the Start Time value is reached.

For more details, tips, and limitations, see the About Contacts Energy Spectra topic.

To Enable and View Data for Contacts Energy Spectra:

See Also:

ENABLE AND VIEW DATA FOR PARTICLES ENERGY SPECTRA

Analyzing data for Particles Energy Spectra involves first turning on the type of collection you want prior to processing (see also About Particles Energy Spectra), and then determining which particle groups you want to involve in that collection. After processing your simulation you can then plot the resulting Curves (Figure 1).

Figure 2.201: Example cross plot showing energy spectra values

It is important to realize that data is only collected after the Start Time value is reached.

For more details, tips, and limitations, see the About Particles Energy Spectra topic.

To Enable and View Data for Particles Energy Spectra:

See Also:

VIEW FREQUENTLY USED TASKS

Use this section to quickly find and perform common tasks in Rocky.

What would you like to do?

See Also:

ENTER INPUT VARIABLES OR MATHEMATICAL FUNCTIONS AS PARAMETER VALUES

You can create Input variables in Rocky (see Defining Your Variables) and then use them in place of actual numerical values in situations where you want more flexibility. These variables can be used alone or within functions.

Important:Verify that your field units are set the way you want before using a variable-or function using a variable-within a field. Even though variables are always saved in the Variables list without units, as soon a variable-or function using a variable-is used within a parameter field, it takes on whatever units are currently set for that field and then those units are recorded for that specific usage in the Expressions list. Changing the units for the field after the variable or function have already been entered only converts the numerical display to reflect the new units; the original variable or function amount and units are still retained. However, you can change the units and value later by editing it in the Expressions list.

Most text fields in Rocky support entering variables or mathematical functions as parameter variables, including three-part text fields. There are a few exceptions to be aware of, however. (See also I cannot enter an input variable or mathematical function into a text field.)

Most of these parametric expressions will be retained while saving a copy of a project for restart purposes, but there are a few exceptions for some Start Time and Stop Time fields. (See also I get a "Links removed" message when I save my project for restart purposes.)

Most text fields will also support the entering of pre-defined mathematical functions (e.g., floor and pow) and constants (e.g., pi and e) that come standard with Python-based programs, including Rocky. And as such, these particular functions and constants cannot be used when defining Input variables.

What would you like to do?

See Also:

REPLACE A PARAMETER VALUE WITH A VARIABLE

See Also:

REPLACE A PARAMETER VALUE WITH A FUNCTION USING A VARIABLE

See Also:

REPLACE A PARAMETER VALUE WITH A PRE-DEFINED MATHEMATICAL CONSTANT

See Also:

CHANGE THE SPEED OF A DEFAULT CONVEYOR

You can change the speed of a default receiving or feed conveyor at any point during the simulation. For example, you might want to measure reclaiming belt power by starting off a simulation with a feed conveyor stopped until a hopper is filled with particles, and then ending the simulation with the conveyor up to full speed.

TO CHANGE THE SPEED OF A DEFAULT CONVEYOR:

See Also:

CHANGE PARTICLE ADHESION

You change particle adhesion when you want a particle to act wetter or "stickier" than normal during a simulation. This might be useful in showing how ore flows through handling equipment during the wet season as compared to the dry, for example.

Tip: It is good practice to calibrate your particle settings to the real-world behavior of the material you are simulating before changing settings like adhesion. You may wish to use the Material Wizard and/or the Calibration Suite to help you with this task.

TO CHANGE PARTICLE ADHESION:

See Also:

SET PARTICLE SIZE RANGES

You set a particle size range-otherwise known as a Particle Size Distribution (PSD)-when you want particles of one shape but different sizes to be used in the simulation. If you set more than one size for a Particle set, Rocky uses a calculation to specify the distribution of sizes within any two dimensions you specify. This helps to more accurately reflect real matter.

When setting size ranges, the following three methods, or Size Types, can be used as a basis for defining your particle sizes (Figure 1):

Figure 2.202: Comparison of the three different Size Types in Rocky

The PSD in Rocky is linear by Particle Mass or, on a semi-log scale, by Particle size and not by number. When you enter the percentage of cumulative mass and then either particle sieve Size, sphere Diameter, or original size Scale Factor (representing the three available Size Types, respectively), these represent points on a semi-log plot. Anything between two points follows the linear rule:

(See also About Adding and Editing Particle Sets.)

For example, if you specify 0.1 and 0.05 (m) particle sizes measured by sieve size, you will get a range of various particle sizes within those two dimensions.

Use the image and procedure below to set size ranges for your Particle sets.

Figure 2.203: Example Size Distribution Settings for Sieve Size

TO SET A PARTICLE SIZE RANGE OR PSD:

Note: The percentage indicated in the final row also indicates what particle mass amount will be of that exact size (no range). For example, if the smallest size you enter is 0.01 m and you have entered 20 for Cumulative %, 20% of the particle mass will be exactly 0.01 m in size in addition to the ranges you have set.

See Also:

SEE SURFACE WEAR ON THE GEOMETRY ITSELF

There are two primary ways you can use Rocky to gain an understanding of how your geometries will wear over time. One way is by enabling surface wear modification, which changes the physical appearance of the geometry as the simulation progresses (Figure 1).

Figure 2.204: Surface wear modification

A second way is to turn on Boundary Collision Statistics (see also About Collision Statistics for Boundaries and then view a color map of the surface intensity (Figure 2), impact velocity, stresses, and more.

Figure 2.205: Color map of surface intensity

These features are independent of each other and are enabled from different areas of the Rocky UI. However, to view either type of wear data, you need to ensure that you have enabled enough geometry triangles prior to processing your simulation. Too few triangles will result in a jagged or blocky representation rather than a smooth one, but too many triangles can slow down your simulation.

Tip: To see a walk-through example of surface wear modification being using to analyze a SAG mill, review Tutorial - SAG Mill in the Rocky Tutorial Guide.

What would you like to do?

See Also:

ENABLE AND VIEW SURFACE WEAR MODIFICATION ON AN IMPORTED GEOMETRY

One way you can use Rocky to gain an understanding of how your geometries will wear over time is by enabling surface wear modification. Turning this feature on for an imported geometry prior to processing changes the physical appearance of the geometry as the simulation progresses (Figure 1).

Figure 2.206: Surface wear modification

To view this type of wear data, you must ensure that you have enabled enough geometry triangles prior to processing your simulation. Too few triangles will result in a jagged or blocky representation rather than a smooth one, but too many triangles can slow down your simulation.

It is important to realize that this data is only collected after the Wear Start value on the Solver | Time tab is reached. This is to allow enough time for the particle flow within your simulation to reach a steady state before surface wear modification calculations begin.

Tips: To see walk-through examples of surface wear modification, refer to the following Tutorials:

TO ENABLE AND VIEW SURFACE WEAR MODIFICATION:

Tips:

See Also:

VIEW A COLOR MAP OF WEAR ON THE DEFAULT BELT OR IMPORTED GEOMETRY ITSELF

When you choose to turn on Boundary Collision Statistics (see also About Collision Statistics for Boundaries and enable wear-related categories such as Intensities, you are able to create and view a color map of the surface intensity (Figure 1), impact velocity, stresses, and more. These color maps can help you analyze the causes of excess wear on your conveyor belts or imported geometries.

Figure 2.207: Color map of surface intensity

TO VIEW A COLOR MAP OF WEAR ON THE DEFAULT BELT OR IMPORTED GEOMETRY ITSELF

See Also:

USE THE 1-WAY FLUENT METHOD TO PROCESS FLUENT AND ROCKY SIMULATIONS

There are five main steps to using the 1-Way Fluent CFD Coupling method to process a 1-Way coupled Rocky and Ansys Fluent simulation, as described below.

Tips:

STEP I: VERIFY THAT ALL ROCKY-FLUENT PROGRAM REQUIREMENTS ARE MET

STEP II: SET UP, PROCESS, AND THEN EXPORT THE CFD SIMULATION

STEP III: SET UP THE DEM SIMULATION IN ROCKY

STEP IV: APPLY 1-WAY FLUENT COUPLING

(See also About Using the 1-Way Fluent Method.)

STEP IV: PROCESS THE COUPLED SIMULATION

See Also:

USE THE 2-WAY FLUENT METHOD TO PROCESS A FLUENT AND ROCKY SIMULATION

There are five main steps to using the 2-Way Fluent method to process a coupled Rocky and Ansys Fluent simulation, as described below.

Note: Both Single phase and Multiphase approaches are covered in this procedure.

Step I: Verify that All Rocky-Fluent Program Requirements are Met

Step II: Set Up the Initial CFD Simulation

Tutorial 14 - DEM-CFD Two-Way Coupling with Ansys Fluent.

Optional Steps:

Step III: Set up the Initial Rocky Simulation

Step IV: Apply 2-Way Coupling

Tips:

Step V: Process the Coupled Simulation

In Rocky, process the simulation as you normally would (see also Start Processing a Simulation from the Beginning) with the following exception:

Rocky automatically opens Ansys Fluent and the Fluent simulation is processed at the same time as the Rocky simulation, depending upon the limitations of your Ansys license. If any incompatibility is found between the Fluent setup and Rocky, an error will be shown in Rocky with additional information. Once the simulations are complete, the data from both are available to see and analyze however you choose. (See also Analyzing a Simulation.)

See Also:

USE THE 2-WAY FLUENT SEMI-RESOLVED METHOD TO PROCESS A FLUENT AND ROCKY SIMULATION

There are five main steps to using the 2-Way Fluent Semi-Resolved method to process a coupled Rocky and Ansys Fluent simulation, as described below.

Note: Both Single phase and Multiphase approaches are covered in this procedure.

Step I: Verify that All Rocky-Fluent Program Requirements are Met

Step II: Set Up the Initial CFD Simulation

Step III: Set up the Initial Rocky Simulation

Step IV: Apply 2-Way Fluent Semi-Resolved Coupling

Tips:

Step V: Process the Coupled Simulation

In Rocky, process the simulation as you normally would (see also Start Processing a Simulation from the Beginning) with the following exception:

Rocky automatically opens Ansys Fluent and the Fluent simulation is processed at the same time as the Rocky simulation, depending upon the limitations of your Ansys license. If any incompatibility is found between the Fluent setup and Rocky, an error will be shown in Rocky with additional information. Once the simulations are complete, the data from both are available to see and analyze however you choose. (See also Analyzing a Simulation.)

See Also:

ENABLE AND VIEW PARTICLE BREAKAGE

Analyzing either Instantaneous or Discrete particle breakage in Rocky involves first turning on breakage parameters for your Particle set prior to processing your simulation (see also About Particle Breakage), and then viewing the results and/or particle-fragment-related Properties or Curves in a 3D View window or graphing them in a plot or histogram window (Figure 1).

Figure 2.208: Example of Instantaneous Breakage being simulated in an HPGR machine

It is important to realize that breakage data is only collected after the Breakage Start value on the Solver | Time tab is reached. This is to allow enough time for the particle flow within your simulation to reach a steady state before breakage calculations begin.

For further details on the specific models, tips, and limitations see the About Particle Breakage topic.

 

2.8.1. To Enable and View Particle Breakage:

1. Set up your simulation as you normally would (see also Set Simulation Parameters), ensuring all of the following:

   1. During the Set Simulation-Wide Parameters step, on the Solver | Time tab, you have set the values you want for both Breakage Start and Breakage Delay after Release. (See also About Solver Parameters.) Tip: It is best practice to set your Breakage Start time to begin after a steady state has been reached for your particle flow.

   2. During the Add and Edit Particle Sets step, you have done all of the following for each of the |Gloss7|s you want breakage enabled:

      1. On the Particle tab, you have ensured that one of the following Shape | Composition option combinations are selected:

         • Either Straight or Custom Fiber Shape | Multiple Element Composition

         • Custom Shell Shape | Multiple Element Composition

         • Solid Polyhedron Shape | either Single Element or Multiple Element Composition

         • Solid Briquette Shape | Single Element Composition

         • Solid Faceted Cylinder Shape | Single Element Composition

         • Solid Custom Convex Polyhedron Shape | either Single Element or Multiple Element Composition

         • Solid Custom Concave Polyhedron Shape| Multiple Element Composition

      2. If you have selected a Single Element particle set, you have done all of the following:

         1. On the Particle | Breakage tab, you have selected the Enable Breakage checkbox.

         2. From the Criteria sub-tab, you have selected the Instantaneous Breakage model you want from the Model list, and have defined its associated parameters.

         3. From the Fragments sub-tab, you have entered the values you want under Limits, have chosen the model you want from the Distribution model list, and have defined its associated parameters.

      3. If you have selected a Multiple Element particle set, you have done all of the following:

         1. On the Particle | Breakage tab, you have selected the Discrete Breakage model you want from the Model list.

         2. You have defined the model's associated parameters.

2. Process your simulation as you normally would. (See also About Starting a Simulation.)

3. After your simulation reaches as least as far as the Breakage Start time, do one or more of the following:

   • From a 3D View window (see also About 3D View Windows), observe the changes to the particle shapes as they fragment and break.

   • From the Data panel, select Particles and then from the Data Editors panel, select either the Properties or Curves tab and then create a plot (see also Graph Data within Rocky by Creating a Plot or Histogram) or visualize the resulting fragments-related Properties in a 3D View window (see also About 3D View Windows).

See Also:

• About Particle Breakage

• About Collecting Data in Rocky

• About Adding and Editing Particle Sets

• About Properties

• About Curves

CREATE AND VIEW A PARTICLE ASSEMBLY

(See also About Particle Assemblies.)

To Create and View a Particle Assembly:

1. Begin setting up your simulation as you normally would (see also Set Simulation Parameters).

2. During the Add and Edit Particle Sets step, do the following:

   1. For each part you want represented in your final Assembly shape, create an individual Particle set. (See also Add a New Particle Set.) Tip: Ensure your Particle set meets the specific criteria for Assembly parts. (Refer to the Assembly Particle Shape Limitations section of the Particle and Input Limitations topic for details.)

   2. Create another new Particle set (see also Add a New Particle Set), select it, and then from the Data Editors panel, do the following:

      1. From the main Particle tab, define the Shape as an Assembly.

      2. From the Shape sub-tab, add a new definition row for each individual part you want to include, and define each's part's position, size scale, and rotation parameters. (See also About Adding and Editing Particle Sets.) Tip: Check your settings in the Particles Details window. (About Particles Details Windows.) Note: For Assembly shapes, the Particles Details 3D view shows the actual position of the part when the size type is Original Size Scale and it is set to 1 (which is the default setting).

   3. Define the rest of the shape settings as you normally would for any other Particle set. (Define what parameters you want on the Size, Movement, and Orientation sub-tabs.) Important:At this point, Rocky will calculate the mass, area, and other properties for the (whole) Assembly particle based on the values you have defined for the Particle sets upon which the individual parts are based, and the size of the parts you have defined within the Assembly. These properties will be calculated accurately by Rocky as long as your individual parts do not overlap; otherwise, the accuracy of these Rocky-calculated properties cannot be guaranteed and you should consider defining them yourself by specifying Custom Properties.

   4. (Optional) If your Assembly shape requires its parts to overlap, and you require accurate mass, area, and other properties for your Assembly particle, consider specifying Custom Properties for your assembly by doing the following:

      1. From the CAD program with which you designed your ideal (Assembly) particle shape, note the Area, Volume, Mass, Geometric Center, Center of Mass, and other properties you want Rocky to use for your Assembly particle shape.

      2. In Rocky, from your Assembly particle's Particle | Custom Properties tab, enable the Change Assembly Properties checkbox, and then enter the information you want Rocky to use. Tip: You can use the colored dots in the Particles Details window to preview where your Center of Mass (blue dot) and Geometric Center (yellow dot) are located.

3. Finish setting up your simulation, process it, and then analyze the results as you normally would.

See Also:

• About Particle Assemblies

• About Adding and Editing Particle Sets

• Particle and Input Limitations

• About Defining and Importing Custom Particle Shapes

ENABLE THERMAL MODELING CALCULATIONS

If you want to observe how particles are affected by temperature changes brought on by the heating or cooling of other items around it, you may set up your simulation to model thermal properties. Turning on Thermal Modeling enables you to simulate conductive heat transfer from particles to other particles, and from particles to boundaries. When used with CFD Coupling methods, it can also simulate convective heat transfer between particles and fluids. (See also Set or Modify Fluid and/or Air Flow Properties.)

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Tip:  For examples and walk-through tutorials of thermal modeling in action, review the following resources:

---

• Tutorial - Conical Dryer in the Rocky Tutorial Guide

• Tutorial 13 - DEM-CFD One Way Coupling With Ansys Fluent (Workbench)

To enable Thermal Modeling in DEM calculations:

1. Set up your simulation as you normally would (see also Set Simulation Parameters), ensuring all of the following:

   1. During the Set Simulation-Wide Parameters step, on the Physics tab, select the Enable Thermal checkbox. (See also About Physics Parameters.) Note: If you decide to enable Intra-particle Collision Statistics, know that the Temperature property will not be available to view on the Particles Details window, but can still be viewed from the main Particles entity or through a 3D View window. (Se also About Intra-Particle Collision Statistics.)

   2. During the Add and Edit Geometry Components step, on the Geometry sub-tab for each of your wall components, set what you want for Thermal Boundary Type and Temperature.

   3. During the Add and Edit Particle Sets step, on the Particle tab for the Particle set(s) you want affected by Thermal, ensure that on the Composition sub-tab for any particles you have you have selected Multiple Elements from the Composition list, that you also set the Conductivity Ratio parameter to the value you want.

   4. During the Modify Material Properties step, on the Materials tab for each of your particle and/or boundary materials, set all of the following parameters:

      • Thermal Conductivity

      • Specific Heat

      • Poisson's ratio (See also About Modifying Material Compositions.)

   5. During the Add and Edit Particle Inputs step, for each Particle Input, set the Temperature of each Particle set row. (See also About Adding and Editing Particle Inputs.)

   6. If coupling your simulation with CFD methods, then during the Set or Modify Fluid and/or Air Flow Properties step, set what you want for the Convective Heat Transfer Law. (See also About Using the 1-Way Fluent Method, About Using the 2-Way Fluent Method, or About Using the 1-Way Constant Method). Note: If coupling your simulation with the 1-Way Constant method specifically, ensure you also set the values you want for constant Temperature, Thermal Conductivity, and Specific Heat. (See also About Using the 1-Way Constant Method.)

2. Process your simulation as you normally would. (See also About Starting a Simulation.)

To enable Thermal Modeling in SPH calculations:

1. Set up your simulation as you normally would (see also About SPH Parameters), ensuring all of the following:

   1. During the Set Simulation-Wide Parameters step, on the Physics tab, select the Enable Thermal checkbox. (See also About Physics Parameters.) The Cleary model for thermal transfer is automatically selected.

   2. During the Add and Edit Geometry Components step, on the Geometry sub-tab for each of your wall components, set what you want for Thermal Boundary Type and Temperature.

   3. If you simulation also involves DEM particles: During the Add and Edit Particle Sets step, on the Particle tab for the Particle set(s) you want affected by Thermal, ensure that on the Composition sub-tab for any particles you have you have selected Multiple Elements from the Composition list, that you also set the Conductivity Ratio parameter to the value you want.

   4. During the Modify Material Properties step, on the Materials tab set all of the following parameters for the fluid material:

      • Thermal Conductivity

      • Specific Heat

2. Process your simulation as you normally would. (See also About Starting a Simulation.)

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Tip:  When you are ready to analyze your simulation (see also Analyzing a Simulation), you might pay special attention to the following Properties (see also About Properties):

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• Temperature (for walls, conveyors, particles and fluids)

• Specific Heat (only for fluids)

• Thermal Conductivity (only for fluids)

See Also:

• View Frequently Used Tasks

ADD A LOGO TO A 3D VIEW

A 3D View of your simulation will always contain the Rocky logo but you can choose to add your own company logo to the view, too. This may be useful in cases where you are showing simulation images or animations to clients and want to brand your work.

Figure 2.209: 3D View window with a Sample Logo added as an Image Overlay

You add a logo image by using the Overlay tab on the Window Editors panel. Logos are added as images and can be positioned anywhere on the 3D View window that you like.

To add a logo to a 3D View:

1. Using separate image editing software, open the logo file you want to use and ensure the display size is appropriate.

2. Ensure your image is saved as either a PNG, JPG, BMP, or PNP file.

3. Open the simulation project to which you want to add the logo and select the 3D View window you want.

4. Using the Overlay tab on the Window Editors panel, add the logo to the 3D View as an Image Overlay. (See also Add or Edit an Image Overlay for a 3D View Window.)

See Also:

• About Using the Window Editors panel to Change a 3D View

• View Frequently Used Tasks

REUSE 3D VIEW WINDOW, WORKSPACE, AND USER PROCESS SETUPS IN OTHER PROJECTS

For projects where you have spent time and effort setting up several 3D View windows, Workspaces, and User Processes just the way you like, you can now export all of that setup criteria and reuse it in other projects. This is an alternative to recording or writing a script to do the setup for you, which requires you to know beforehand exactly how you want your views and processes to work. With this feature, you can decide after the fact whether you want to reuse the setup for another project or not.

This can be useful in cases where you have already run several similar simulations but your client suddenly wants to see new views or processes. By using this feature, you can set up the new views and processes in one project, and then apply those same views and processes to the rest of the projects in your set.

Rocky enables you to export this setup criteria to either a rocky_template file or to the clipboard, and even lists each component that was exported in a separate dialog (Figure 1) for confirmation purposes.

  Example dialog that appears after exporting project context

In your new project, you can then choose to import the saved criteria from those same two locations.

Once imported, Rocky simply creates new 3D View windows, Workspaces, and User Processes to match what was exported. If you already have 3D View windows and User Processes in your project at the time of Import, Rocky will retain these items while adding the new ones to the project.

To export 3D View window, Workspace, and User Process setups for use in other projects:

1. Ensure that your 3D View windows, Workspaces, and User Processes are set up the way you want.

2. From the File menu, point to Export project context and then do one of the following:

• To ensure reuse of the project context for longer than just the immediate timeframe, select To file, and then do all of the following: a. From the Save project context dialog, select the location to which you want to save the rocky_template file, name it in the File name box, and then click Save. b. In the Finished exporting context dialog, review the items listed, and then click OK.

• To reuse the project context for only the immediate timeframe, select To clipboard, and then in the Finished exporting context dialog, review the items listed, and then click OK.

  The 3D Window, Workspace, and User Process setups are ready to import into another project.

To import 3D View window, Workspace, and User Process setups previously exported out of another project

1. Ensure the project that you want to apply the previously exported setups is open in Rocky.

2. From the File menu, point to Import project context and then do one of the following:

• To import from a previously exported file, select From file, and then from the Restore project context dialog, locate and select the rocky_template file you want to use, and then click Open.

• To import from the clipboard, select From clipboard.

  The 3D Window, Workspace, and User Process setups you previously exported are added to the project.

See Also:

• About Creating and Using PrePost Scripts

• Create and Modify a 3D View

• Filter Views and Data with User Processes

• About Workspaces

• View Frequently Used Tasks

SET UP A NEW GPU CARD

When setting up a new GPU card for use with Rocky, there are two steps you can take that might help make processing your simulations on GPU smoother and faster:

• Turn off the Windows Timeout Detection and Recovery (TDR)

• Enable double-precision processing

See below for specific instructions.

Turn off Timeout Detection and Recovery (TDR) for a GPU card

Application: This procedure is particularly useful when you have a single NVIDIA GPU card. But it can also be useful for any GPUs used by Rocky in general.

Symptom: Your Rocky simulations sporadically stop during the middle of a complex simulation, resulting in an incomplete calculation and an error (Figure 1). This is caused by Windows believing the GPU card is non-responsive because it is taking longer than expected to return an answer on a difficult calculation. Turning off TDR for your GPU allows the card the necessary time to execute the computation.

Figure 2.210: Error seen in Rocky when TDR causes the GPU to stop processing

To turn off TDR for a GPU card:

1. Ensure that you have successfully installed your GPU card and associated drivers, and have restarted your computer.

2. Download and install the latest NVIDIA Nsight Visual Studio Edition from Nvidia.   Figure 2: Installation confirmation screen for Nsight Visual Studio Edition

   Notes:

   • As seen in Figure 2 above, you will need only to install the Nsight Monitor option; the Nsight Visual Studio option is not necessary.

   • You may need to Subscribe as a developer (free of charge) on the Nvidia website, if you haven't done it before, in order to download the Nsight Visual Studio Edition (Figure 3).

     Figure 3: Subscribe to Nvidia developer program

3. Restart your computer.

4. From the Windows Start menu, under NVIDIA Corporation, click Nsight Monitor (Figure 4).   Figure 4 Nsight Monitor in Windows Start menu A new Nsight Monitor icon appears in your Notification Area.

5. From your Notification Area, right-click the Nsight Monitor icon and then select Options (Figure 5).   Figure 5: Nsight Monitor in Notification Area

6. From the NVIDIA Nsight Options dialog, on the General tab, set WDDM TDR enabled to False (Figure 6).   Figure 6: NVIDIA Nsight Options dialog

7. Click OK.

8. Restart your computer.

Enable double-precision processing for your GPU cards

Application: You have one or more GPU cards from the NVIDIA Titan family.

Symptom: You are seeing slower than expected results on your Titan family GPU card. This could be a result of not yet enabling double-precision processing. Doing so will speed up certain Rocky calculations, thereby reducing your overall processing time, at the expense of slowing down your graphics visualization performance. Additionally, it has been found that a Titan card using double precision will take longer when simulating Spheres (~20%), but will be faster when simulating shaped particles (~200%).

To enable double-precision processing for your GPU cards:

1. Ensure that you have successfully installed your Titan card(s) and associated drivers, and have restarted your computer.

2. Right-click your Windows desktop, and then click NVIDIA Control Panel (Figure 7).   Figure 7: Windows desktop right-click menu showing NVIDIA Control Panel option

3. In the NVIDIA Control Panel window, do all of the following:

   1. From the Select a Task list, select Manage 3D settings.

   2. In the Global Settings tab under Feature, select Double precision and then from the drop-down list, ensure all your Titan GPU cards are enabled (checked) (Figure 8).   Figure 8: Manage 3D Settings section in the NVIDIA Control Panel

   3. Click OK.

4. Restart your computer.

See Also:

• Best Practices for Faster Processing