Dear PyFR developers and users,
I have successfully reproduced the LES simulation of the flow around a sd7003 airfoil presented in the paper (On the utility of GPU accelerated high-order methods for unsteady flow simulations: A comparison with industry-standard tools, 2017 JCP). The results are quite good.
Now, I want to perform LES of flow around a NACA0015 airfoil with angle of attack near stall angle and Reynolds number of around 60,000. The first difficulty encountered is the mesh generation. I have the following problems:
1. In the PyFR user guide, the free software Gmsh is used to generate mesh. As seen in the above JCP paper by the developers, the mesh used in LES of flow past airfoil is complex. The mesh is refined near the airfoil and in the rectangular wake region, and then quickly coarsened outside these regions. So, is there any example script that can be read into Gmsh to generate such a complex mesh for a LES simulation or any guide for complex mesh generation?
2. For a LES simulation, the grid resolution (dx, dy, dz) in streamwise, wall-normal and spanwise direction respectively must satisfy certain criterion. According to the above JCP paper, y+ in the first layer of mesh near wall is around 0.4. So, what is the grid spacing in streamwise (dx) and spanwise (dz) direction if the Reynolds number is around say 60,000?
3. Pointwise17.3R4 can generate mesh for PyFR. However, its seems that in Pointwise, one cannot specify periodic boundary conditions and there is no option for periodic BC. So, how can we impose the periodic BC when pointwise is used.
It will be greatly appreciated if anyone can help answer the above questions or give some suggestion.
Best regards,
Jianguo