[L/D]

Hi, I am simulating steady, incompressible, and turbulent flow over a NACA 0012 airfoil at an angle of attack of 10 degrees. I'm currently studying all of the different turbulence models and when I did a simulation with the transition k-kl-w and transition SST model, there are these weird pressure spots that occur. I was wondering if anyone knows what they are because it's causing my pressure coefficient graph to have this weird wiggle. Attached is pictures of my mesh, the pressure spots, and my Cp plot. Thanks.

[CFDKareem]

Hey L/D, what is the Y+ value on the wall of the airfoil?

[L/D]

Hello, the Y+ is a little less than 1

[CFDKareem]

So my guess looking at the pictures of the mesh you supplied are that there are some really small elements in the inflation layer that are adding some error to your calculation. I can see that the cells in your inflation layer are perfect squares. It is okay for these cells to be elongated in the direction of the flow. Try reducing the (I assume) edge sizing value on the airfoil well maintaining the cell height in the normal direction. This will reduce the number of elements well still maintaining your Y+ value.

This will also help with the transition from your boundary layer to the unstructured mesh. As you transition from the inflation to the tet mesh you can see an abrupt step change in the cell volume. There are a series of highly skewed elements in that transition layer. Although I don't think this is directly causing the error, it is a good practice to avoid dramatic changes in cell size.

Try this out and let me know how it looks!

[L/D]

Ok i'll try it out. Thank you very much for the feedback.