How to... correctly mesh CFD model in Ansys CFX and Fluent

Meshing is one of the decisive steps in both CFD and FEA analysis. The correct execution of the mesh and optimization in terms of the number of finite elements makes the work of every Ansys user much easier. 

Example of CFD mesh in Ansys Workbench

The quality of the mesh will determine the speed of convergence of the partial equations and the correctness of the obtained distributions (in terms of physical phenomena). Optimization for the number of finite elements will shorten the entire calculation process while maintaining the correctness of the model. Also, an extremely important aspect (if there is such a possibility in the analyzed model) is the selection of the appropriate type of finite element. But we will deal with this in the following entries. 

In this post, the general principles of discretization method in CFD simulations will be presented. 

First of all U need to simplify the geometry of the model. Delete all irrelevant elements that will not affect the physics of the analyzed phenomenas. Try to delete micro and mini elements, chamfers, fillets etc. 

Under meshing u need to follow two basic (general) rules:

1) try to avoid empty regions in the computational domains 

2) Check that Ur model doesn't have overlapping elements (U can generate mesh quality to see this error)

After that U must following by the goal function  - MESH QUALITY (computational cost). Very good otion to optimize this is to make sensivity analysis where U check imbalances which are dependent from element size, element type and time step size. 

A very improtant principle of mesh in CFD is the thickening of the elements in the places of walls and bottlenecks areas. This principle distinguishes CFD meshing from other analyzes (for example structural). 

Correct faces pick in Ansys Meshing 

By defining named selection areas in the simple way U can do this type of CFD mesh (red frame, yellow frame). In the picture above thickening was used in the contact area between fluid and solid domain. After discretization (meshing) U can check interested regions by creating section planes. Instructions for creating cross-sections (section planes) can be found in the figure below.

How to make section plane in Ansys Workbench