Symmetry faces on the top and bottom faces of the external flow domain: While it’s not technically incorrect to apply symmetry faces there, it is more commonly recommended to define slip walls.
Pressure input in Pressure Outlet boundary condition for incompressible flows: In the case of incompressible flows, the pressure input in the Pressure Outlet boundary condition is typically specified as gauge pressure. The general approach is to use a reference pressure of 0 Pa (gauge pressure). This means that the pressure value you input is relative to the reference pressure.
y+ value and wall resolution: When manually defining the inflation layers, it is crucial to ensure that the y+ values fall within an appropriate range. For wall functions, a common guideline is to maintain a range of 30 < y+ < 300, while for the full resolution approach, y+ should be less than or equal to 1. In the current case, it seems that there are regions on the VTOL with y+ values exceeding 1000, indicating that the wall cannot be properly resolved. This can lead to inaccuracies in the flow simulation and should be addressed by adjusting the mesh and/or refining the inflation layers.
Any tips on how to refine the inflation layers?
How did you check that some regions on the VTOL exceed 1000.
I recently successfully reran it with 3 layers. However the results are skewed. The coefficient of drag is extremely low and the coefficient of lift is negative. Any tips will be great!
You will also find recommendations on how you can control your inflation layer manually in the very same documentation page. Please let me know how it goes, and if it helps to resolve the issue.
