This section describes the basic process for using the Ansys Meshing application to create a mesh as part of an Ansys Workbench CFD/fluids analysis. Refer to Strategies for CFD/Fluids Meshing in Ansys Workbench for information about different CFD/Fluids meshing strategies. Refer to the Ansys Workbench help for detailed information about working in Ansys Workbench. There are four basic steps to creating a mesh:

Create Geometry

You can create geometry for the Meshing application in the Ansys Discovery SpaceClaim or Ansys DesignModeler application. You can also import the geometry from an external CAD file.

The Meshing application requires you to construct solid bodies (not surface bodies) to define the region for the 3D mesh (for 2D simulations a sheet body can be used). A separate body must be created for each region of interest in the fluids simulation. For example, a region in which you want the fluids solver to solve only heat transfer must be created as a separate body. Multiple bodies are created in the DesignModeler application by using the Freeze command, see Freeze in the DesignModeler help for details.

It is best practice to explicitly identify any fluid regions in the model as fluids rather than solids.

For new users or new models it is often useful to first generate a default mesh, evaluate it, and then apply the controls described in Define Mesh Attributes as appropriate to improve various mesh characteristics.

Define Named Selections

During the fluids simulation setup, you will need to define boundary conditions where you can apply specific physics. For example, you may need to define where the fluid enters the geometry or where it exits. Although it may be possible to select the faces that correspond to a particular boundary condition inside the solver application, it is rather easier to make this selection ahead of time in either the CAD connection, the Ansys DesignModeler application, or the Meshing application. In addition, it is much better to define the location of periodic boundaries before the mesh is generated to allow the nodes of the surface mesh to match on the two sides of the periodic boundary, which in turn allows for a more accurate fluids solution.

Creating a Named Selection will affect how the mesher treats that topology. For details, see Protecting Topology Defined Prior to Meshing.

You can define the locations of boundaries by defining Named Selections, which can assist you in the following ways:

For more information:

Define Mesh Attributes

The mesh generation process in the Meshing application is fully automatic. However, you have considerable control over how the mesh elements are distributed. To ensure that you get the best fluids solution possible with your available computing resources, you can dictate the background element size, type of mesh to generate, and where and how the mesh should be refined. In general, setting up the length scale field for your mesh is a three-step process, as outlined below:

Generate Mesh

When you are ready to compute the mesh, you can do so by using either the Update feature or the Generate Mesh feature. Either feature computes the entire mesh. The surface mesh and the volume mesh are generated at one time. The mesh for all parts/bodies is also generated at one time. For help in understanding the difference between the Update and Generate Mesh features, see Updating the Mesh Cell State.

For information on how to generate the mesh for selected parts/bodies only, refer to Generating Mesh. The Previewing Surface Mesh and Previewing Inflation features are also available if you do not want to generate the entire mesh at one time.

Once the mesh is generated, you can view it by selecting the Mesh object in the Tree Outline. You can define Section Planes to visualize the mesh characteristics, and you can use the Mesh Metric feature to view the worst quality element based on the quality criterion for a selected mesh metric.