Calculation Types

Determine how calculations are performed in your simulation. By default, Discovery will automatically determine the calculation type based on the physics specifications in your simulation. If you prefer to explicitly set the calculation type, go to Simulation Options in the ribbon of the Simulation tab and click Specify calculation type. Choose between performing a Static or steady-state or Time-dependent calculation.

Select Static or steady-state to determine the long-term behavior of a system that does not change over time.

Select Time-dependent to follow behavior over a specified duration (also called time-history analysis or transient simulation). You can then specify the simulation duration in seconds. If you do not specify a duration, the simulation will continue until interrupted. A time-dependent analysis, by definition, involves conditions that are a function of time.

The following table provides a description of different steady-state (static) and time-dependent physics applications.

Physics	Calculation Type	Description
Structural	Static	Used to determine the displacements, stresses, strains, and forces in structures or components caused by loads that do not induce significant inertia and damping effects. Steady loading and response conditions are assumed. That is, the loads and the structure's response are assumed to vary slowly with respect to time.
Thermal	Steady-state	Used to determine temperatures, thermal gradients, heat flow rates, and heat fluxes in an object that are caused by thermal loads that do not vary over time. A steady-state thermal analysis calculates the effects of steady thermal loads on a system or component. Engineers often perform a steady-state analysis before performing a time-dependent thermal analysis, to help establish initial conditions.
Fluid flow	Steady-state	Used to determine fluid velocities, pressures and temperatures caused by fluid and thermal conditions that do not vary over time. A steady-state fluid analysis calculates the effects of steady fluid and thermal conditions for either internal or external fluid domains. Engineers often perform a steady-state fluid flow analysis to determine flow characteristics (velocity, temperature and pressure) that do not vary with time.
Thermal	Time-dependent	Used to determine temperatures and other thermal quantities that vary over time. Many applications may involve the variation of temperature distribution over time, such as with cooling of electronic packages or a quenching analysis for heat treatment. Also of interest are the temperature distribution results in thermal stresses that can cause failure. In such cases the temperatures from a time-dependent thermal analysis can be used as inputs to a structural analysis for thermal stress evaluations. Many heat transfer applications such as heat treatment problems, electronic package design, nozzles, engine blocks, pressure vessels, fluid-structure interaction problems, and so on involve time-dependent thermal analyses.
Fluid flow	Time-dependent	Used to simulate systems where the flow behavior varies over time. Enabling time dependence is sometimes useful when attempting to solve steady-state problems that tend toward instability (for example, natural convection problems in which the Rayleigh number is close to the transition region). It is possible in many cases to reach a steady-state solution by integrating the time-dependent equations.

Physics Combinations and Calculation Types provide a summary of the physics available based on the calculation type and simulation stage.

In addition, for a structural simulation, a natural frequency or modal analysis is available.