Tips & Tricks

Boundary Layer meshing in CFD-VisCART

In order to accurately capture flow field characteristics, a fine mesh near boundary walls is often needed. This is commonly referred to as the Boundary Layer mesh or simply, Boundary Layers. When dealing with structured meshes, one would cluster grid points near specific boundaries before building mesh faces and blocks. But for an automated mesher, dedicated algorithms are needed to generate boundary layer cells. Both CFD-GEOM and CFD-VisCART are capable of generating boundary layer meshes, and they share the same core algorithm.

"Preserve Feature" option in CFD-VisCART

When dealing with the multi-domain mesher in CFD-VisCART, the ‘Preserve Feature’ option can help you get a mesh that closely follow the original geometry. The meshing algorithm controls the refinement based on the detected ‘Critical Features’ or ‘Outlines’. Therefore, it is very important to detect critical features and outlines prior to mesh generation.

Local cell size control option in CFD-VisCART

It is often necessary to refine or coarsen the mesh in some regions of your model, whether it be to allow the solver to correctly capture gradients of variables (refinement), or reduce the mesh density in some areas to lower the total cell count. In CFD-VisCART, there are many options that enable local mesh refinement.

Surface mesh coarsening option for Shrink-Wrapped meshes

When generating a shrink-wrapped surface mesh, one could end up with a large number of faces (triangles) in an attempt to capture small features. The Mesh Decimation tool in CFD-VisCART allows the user to reduce the number of faces without losing features preserved during the skrink-wrapping process.

CFD-FASTRAN/CFD-ACE+ coupling for thermal environment simulations

In certain applications, different regions of the computational domain experiences flow conditions that are so different that it is very difficult for a single solver to produce accurate results at the extremes. In many situations, such problems can be separated and solved using loosely coupled solvers. Each solver is chosen to provide highly accurate solutions for the prevailing flow conditions.

Cell Size Growth Control in CFD-VisCART

In CFD-VisCART, the Cartesian cells can split or grow by a minimum factor of 2 because of the intrinsic cartesian-cell-splitting algorithm. Due to this, in some cases, there is a chance that the mesh could grow from dense (at the wall) to coarse (away from the wall) within a short distance.

Wireframe Display in CFD-VisCART

Rotation, zoom, pan and other graphical operations require re-drawing of the model in the new position within the graphics window. When dealing with large models, these operations can slow down considerably due to the huge amount of graphical data that needs to be processed and re-drawn.

Avoiding Chimera Errors in CFD-FASTRAN

This note discusses a common error encountered by users when trying chimera meshes in CFD-FASTRAN. Such errors are easy to avoid and hopefully this note will assist you.

Motion Model Dependencies in CFD-FASTRAN

Moving-body models available in CFD-FASTRAN are highly suited to simulate complex prescribed and six-degree-of-freedom (6DOF) motions of rigid bodies. In many engineering problems, this translates to multiple bodies moving relative to one another.

Visual Display of Bad Cells in CFD-VisCART

Most models have certain parts or regions where the grid density needs to be higher than other areas to accommodate for steep curvatures, sharply changing topology, etc.