Steered Adaptive Meshing in ADINA — for CFD

A specific difficulty in many CFD solutions is to establish a good mesh. For this reason much effort has been focused on mesh generation schemes. However, in general, the "best mesh" depends on the problem solved, that is, the solution to be obtained, and frequently cannot be established prior to the analysis — the best mesh needs to be established iteratively as the solution is calculated.

ADINA offers a powerful feature for CFD and FSI solutions, with which the user can ask the program to establish new meshes depending on various criteria, as part of the complete solution process. The scheme is based on the algorithms published in the reference given below. The user can use the feature in an automatic mode, or in a user-steered mode. Hence the feature is called "Steered Adaptive Meshing" or in brief, SAM. The objective in this Brief is to illustrate this feature in a simple but instructive CFD solution.

The steered adaptive meshing feature in ADINA is fully integrated into the ADINA User Interface for CFD and FSI modeling, for both the manual and the automatic mode. Of course, the automatic mode is most convenient when mesh repair or adaptive mesh adjustment need to be carried out many times, while the manual mode allows the user to directly control the mesh quality and memory usage. Users can also use these modes in combination, for various stages of the complete analysis.

It is very easy to use the SAM feature. We demonstrate the use of steered adaptive meshing in automatic mode in Primer Problem 48. A schematic of the problem is shown in Figure 1. Figure 2 shows the final mesh, and a typical band plot of the results is shown in Figure 3. The problem is presented in 2 sections so that it is easier for you to review certain parts if necessary.

Figure 1  Schematic of the problem in Primer Problem 48

Figure 2  Final mesh generated

Figure 3  Band plot of y-velocity

Reference

• K.J. Bathe and H. Zhang, "A Mesh Adaptivity Procedure for CFD and Fluid-Structure Interactions", Computers & Structures, 87:604-617, 2009

Keywords:
Meshing, adaptive meshing, mesh repair, CFD, FSI, free-form meshing, error control, 2D and 3D solutions