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-   -   Very strange results with turbulent simpleFoam simulations on airfoil (https://www.cfd-online.com/Forums/openfoam-solving/254497-very-strange-results-turbulent-simplefoam-simulations-airfoil.html)

tnee3 February 14, 2024 16:29

Very strange results with turbulent simpleFoam simulations on airfoil
 
3 Attachment(s)
Hi!

I’d firstly like to apologise for how open ended this post is going to be. I’m trying to run 2d turbulent simulations of an airfoil using simpleFoam, and meshing with snappyHexMesh.

When I run the case without the viscous layers added, obviously my values are wrong as the boundary layer is not resolved but it runs okay. However when I add the viscous layers, the simulations produce very strange velocity plots in paraview. I will attach some of these plots below.

Attachment 98498 Attachment 98499

I know this is very broad and I’m sorry but I’m completely stumped by it. Any help on this would be really great, thanks!
I’ve also attached my snappyHexMeshDict, controlDict, and initial conditions for velocity pressure and turbulence model parameters (k-omega SST model). Please let me know if there’s any other files I should upload.
Attachment 98500

samisafarini February 15, 2024 05:38

Is the simulation for a wind tunnel? it seems odd that your top and bottom are nonslip. I find setting a pressure of 0 gives me problems have you tried setting it as absolute atmospheric i.e. 100kpa?
Can you share the whole sim folder with us?

tnee3 February 16, 2024 10:47

Hi there, thank you for responding to me, sorry I took a while to respond.

My issue actually ended up coming down to my mesh, it simply was not good enough. I was also using renumberMesh to optimise it as I read somewhere to do that and for whatever reason that was giving me the second very strange plot. I have somewhat fixed the issue now, but still need to refine the mesh further to solve the boundary layer. Thanks again for the response though!


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