Ansys Fluent supports the following capabilities when used in a System Coupling analysis:
Force and displacement data transfers on wall boundaries (including walls in sliding mesh zones), porous jump boundaries, and porous zone interfaces:
Input of incremental displacements data from System Coupling allows moving and deforming mesh specification on boundary wall regions (including walls in sliding mesh zones), porous jump boundaries, and porous zone interfaces (via a zero-thickness porous jump boundary). Note the additional System Coupling option in the Dynamic Mesh Zones dialog box. For more information, see Specifying the Motion of Dynamic Zones.
Output of force data on boundary wall regions (including walls in sliding mesh zones), porous jump boundaries, and porous zone interfaces (via a zero-thickness porous jump boundary). Fluent can serve the total force variable (viscous and normal) on all wall boundaries (with or without enabling the System Coupling option in the Dynamic Mesh Zones dialog box). For details about the forces transferred from the wall and porous jump boundaries, see Variables Available for System Coupling.
Thermal data transfers on wall boundaries and cell zones:
Input of temperature data, heat flow data, and heat transfer coefficient data from System Coupling on all wall boundaries. Note the additional via System Coupling option on the Thermal tab of the Boundary Conditions dialog box.
Input of surface heat rates from System Coupling (via Maxwell) on coupled walls adjacent to a solid zone.
Input of heat rate data from System Coupling on cell zones.
Output of temperature data, heat flow data, and heat transfer coefficient data to System Coupling on all wall boundaries (with or without enabling the System Coupling option in the Dynamic Mesh Zones dialog box).
Output of temperature data to System Coupling from cell zones.
Electric arc propagation on fluid volumes between Fluent and Ansys Maxwell.
Input of Lorentz force, temperature, and heat flow data on cell zones from System Coupling.
Output of electrical conductivity, temperature, and heat flow data to System Coupling from cell zones.
Time-dependent motion and excitation on coupled and non-coupled bodies :
Supported for System Coupling's CLI and GUI (not for System Coupling in Workbench).
Motion can be defined on coupled bodies.
Motion must be defined with constant velocity in Fluent and consistent/matching displacement in Maxwell (variable velocity not supported.)
Currently supported only for Maxwell/Fluent electromagnetic-thermal analyses.
Motion can be specified for rigid bodies and cell zones.
Can set solid cell zone movement as rigid body motion using total displacement (vs. System Coupling time) relative to the original cell zone location.
Motion can be set using a profile.
This motion corresponds to the displacement at the end of the current coupling step.
Fluent's motion should be set to be consistent with Maxwell's.
For command-line runs, active surface thermal coupling between two Fluent applications, one running in transient and one running in steady state.
For such mixed type of simulations, Fluent has been extended to support time averaged (HTC or
) data transfers from transient to steady state Fluent. Within a coupling step, a new sub-stepping option is introduced in Fluent which uses a smaller step size than the specified time step size in System Coupling. This sub stepping option will be used to accumulate the unsteady thermal data of HTC or
. This accumulated thermal data will be used to compute time averaged data
according to the following formulation:where
is the physical time step size and 
is the thermal scalar value (HTC or 
).Also, the Fluent coupling code has been extended to compute HTC based on Wall Functions and Y plus. By default, Fluent coupling code uses a wall adjacent based HTC method.
All these HTC calculation methods and sub-stepping options can be accessed by TUI commands at this location:
/define/models/system-coupling-settings/htc-calculation-settings> htc-calculation-method/ unsteady-statistics/
Fluent supports only these two quantities (HTC and
) for time averaged data transfers and uses an explicit coupling approach
(one coupling iteration per coupling step). Apart from time averaged thermal data of HTC and
, Fluent also supports instantaneous values of HTC based on Wall
Functions or Y plus for data transfers.
Data transfers from wall boundaries that are in Fluent sliding mesh zone or rigid body zone.
The use of triangular and quadrilateral faced interface cell types.
Full support for local and distributed parallel solver execution.
Custom solver input and restart files (when using System Coupling's GUI or CLI).
Convergence data for all equations (for example, continuity, momentum, and energy convergence data) is shared with the system coupling service at run time. Monitor data is shared if the monitor point has an iteration frequency set. If the monitor point has a time step frequency set, monitor data will not be shared with System Coupling.
In Workbench, this data from Fluent can be charted in conjunction with other data in the system coupling chart at all available intervals. Intermediate data points are not artificially created in the system coupling chart.
Monitor data can also be plotted in Fluent Solution Monitoring.
Note the following limitations when using Fluent in a System Coupling analysis:
Using System Coupling with the Remote Solver Manager (RSM) in Fluent is not supported. If attempted, you will receive the following message:
Solution updates for Fluent systems participating in System Couplings must run in the foreground. This change has been automatically applied.
It is recommended to use Unified remeshing for all system coupling cases with dynamic mesh remeshing (except 2.5D, which is not supported by unified remeshing). Cases coupling Fluent with Ansys Structural in Workbench may experience errors if using Methods-Based remeshing.
When using a wall and wall-shadow pair in Fluent as System Coupling interfaces, you'll need to create a duplicate surface in Mechanical. These will be paired with two sets of shell elements in Mechanical. For more information, see Coupling Thin Surfaces in CFX in the Mechanical User's Guide.
Fluent must use a 3D mesh, with data transfer regions consisting of element faces within the 3D mesh. Data Transfer regions cannot exist in 2D meshes (where the data transfer region would be a line/curve).
Data transfer regions on the coupling interface cannot contain hanging nodes (which result from hanging node adaption and may be in hexcore or CutCell meshes if you have disabled their conversion when reading the file).
For FSI, the mesh topology on a System Coupling boundary in Fluent must remain fixed for the duration of the analysis. This means that dynamic remeshing cannot be used on the System Coupling boundary, but interior nodes away from the System Coupling boundary can still be remeshed during the solution.
To transfer forces on wall and wall-shadow pair, you need two surfaces in Mechanical to match the two surfaces in Fluent. In this case, you cannot use a single set of shell elements in Mechanical. An example of a wall and wall-shadow pair is two different fluids on either side of a zero-thickness internal wall in Fluent.
The non-iterative time-advancement (NITA) scheme in Fluent cannot be used in a System Coupling analysis.
When executing design points for System Coupling cases where Fluent is a participant, Program Controlled should not be used for Fluent Initialization Method.
Shell conduction is not available when the Fluent region is set up to receive thermal data via System Coupling.