[Ra0501]

Hello everyone,

For my master's thesis, I am conducting a study on the aero-structural optimization of an F1 wing. I'm not very experienced with CFD simulations and I’m struggling to complete the grid convergence. It’s a 2D simulation of a multi-element (mainplane + flap) with high curvature and low Mach (I need to validate the Cp from experimental data), and I’m using RANS with the SST turbulence model.

My main concerns are related to the numerical aspect, specifically about the correct convergence criteria to adopt and, at this point, the quality of the mesh. From what I understand, I should probably adjust the CFL number. However, I’ve run other simulations with CFL=10 and CFL=5; in the first case, I obtained roughly the same results, while in the second case, for finer meshes, the solution does not stabilize and keeps oscillating. I’ve set the convergence criterion based on the drag residual.

I’m attaching the config files and some of the results I’ve obtained. I hope someone can provide advice and tips to achieve the grid independence, especially regarding the numerical setup.

Thank you!

[bigfootedrockmidget]

First thing to do is to make sure that your simulations have converged sufficiently. All residuals should converge to at least R=-10, but preferably to machine precision.
Do you have some residual plots of the convergence? You can use paraview to load the history file with the residuals and make a plot.



You can have a look at the Verification and Validation results (and the setup) of our multi-element case:
https://su2code.github.io/vandv/30p30n/

[Ra0501]

Here there are the plot of the residuals, They don’t reach -10 but are flat. I also attached the y+ plot and the a screenshot of the Coarse and the Superfine mesh I used. Now I’ll try to use the setup you suggested.
Thank you for now.

[bigfootedrockmidget]

Can you share the entire coarse mesh somewhere, and is there a paper describing measurements or other simulation results for this configuration?