External Solver dialog box (Multiphysics)

Modeling Object
Name	Sets the name for the modeling object.
Label	Sets a unique numeric identifier for the modeling object.
Properties
Description	Lets you enter a description for the modeling object.
Settings tab
Dimensionality	Sets the dimensionality of the CFD model. In can be either 2D or 3D.
Executable Location	Sets the path and name of the executable file for the external CFD solver.
Additional Command Keywords	Sets additional command keywords for the specified external CFD solver.
Input File Location	Sets the path and name of the input file for the external CFD solver. This file contains the CFD model including the boundary conditions.
Iteration Limit	Sets the maximum number of iterations the external CFD solver performs without converging the steady-state CFD solution.
Model Alignment tab
Type	Specifies how the CFD model is aligned with the Pre/Post model.No AlignmentAssumes that the two models are properly aligned and no additional alignment is necessary.Three Point MethodAligns the two models using three specified corresponding points in both models. You can also dilate the coordinates from the CFD model to scale to the Pre/Post model when you select the Dilate External Solver Coordinates to Scale to Pre/Post Model check box. TransformationAligns the CFD model with the Pre/Post model by applying a translational offset, a rotational offset, and a scaling.
Specify Point 1Specify Point 2Specify Point 3	Available when Type is set to Three Point Method.Let you select three points in your Pre/Post model.
External Solver Point 1 CoordinatesExternal Solver Point 2 CoordinatesExternal Solver Point 3 Coordinates	Available when Type is set to Three Point Method.Set the coordinates of the three corresponding points from the CFD model in the X, Y, and Z boxes.
Translational Offset	Available when Type is set to Transformation.Applies a translational offset to the nodes of the CFD model. You enter the translational offset distances in the X, Y, and Z boxes.
Rotational Offset	Available when Type is set to Transformation.Applies a rotational offset to the nodes of the CFD model. You enter the angles of rotation in the Rotation about X, Rotation about Y, and Rotation about Z boxes.
Scaling	Available when Type is set to Transformation.Applies a scaling to the coordinates of the CFD model. You enter the scaling factor value in the Scale Factor box.
Coupling External Solver Convergence Control tab
Convergence Criterion	Sets the convergence value for the CFD solver. This value must be a positive number greater than 0 but less than 1.Multiphysics monitors the convergence of the external CFD solver according to the Convergence Criterion and Convergence Norm values. For a given time step, the external CFD solver transfers data to the thermal solver when one of the following is reached:The Iteration Limit (maximum number of CFD solve iterations)The Convergence CriterionThe software calculates convergence by creating a ratio that compares the values of the CFD solution variables for the current step to the values at the previous step. The ratio is created according to your selected Convergence Norm. When this ratio becomes less than your specified Convergence Criterion, the step is considered converged.
Convergence Norm	Specifies the type of norm that is used to calculate the convergence ratio for the CFD solution variables.MAXUses the maximum norm convergence criterion,	Δx	max/	x	mean.L2Uses the L2 criterion,
Relaxation	Sets a relaxation factor to the CFD solution variables to limit the amount these variables can change from one step to the next. A smaller value applies more relaxation to the solution variables.The solution with a relaxation factor may take longer to complete, but it may be required for a successful convergence. The resulting converged solution is generally the same with or without a relaxation factor.The relaxation factor f is applied as follows:vtarget(i)=f∙vsource(i) + (1–f) ∙ *vtarget(i-1)*where:vtarget(i) is the solution variable applied to the target solver at iteration i.vsource(i) is the solution variable computed from the source solver at iteration i.	vtarget(i)=f∙vsource(i) + (1–f) ∙ vtarget(i-1)				where:vtarget(i) is the solution variable applied to the target solver at iteration i.vsource(i) is the solution variable computed from the source solver at iteration i.
vtarget(i)=f∙vsource(i) + (1–f) ∙ vtarget(i-1)				where:vtarget(i) is the solution variable applied to the target solver at iteration i.vsource(i) is the solution variable computed from the source solver at iteration i.

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Coupling to external CFD solvers

External Solver dialog box (Multiphysics), Simcenter 3D 2021.1 Series

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