Workbench/Numerical Wind Tunnel/AFront computation with holes & cavities

[boucaron]

Hi,

I performed a test using a 1-square-meter cube to compare the frontal area (AFront) between two scenarios:

• A closed cube (expected AFront = 1 square meter).
• A cube with a large cavity and a tiny input hole (expected AFront = 1 square meter as well). The AFront for the cube with the large cavity is slightly bigger than 1 square meter (less than 2). I was expecting the AFront of the cube with the cavity to match that of the closed cube.

As workaround I compute the AFront in the CAD and recompute the drag coefficients (cs/cr/cl)

[hkroeger]

Dear boucaron,

thanks for pointing this out! Can you provide your test geometry and input files? Please note that the projected surface is computed from the meshed patch using the OpenFOAM tool "projectedArea" (part of InsightCAE) and not from the initial geometry. Thus there might be deviations expected, if the mesh is coarse.

Regards, Hannes

[boucaron]

Yes, please find the attached STLs. Tests.zip

Default Settings Orient the cube with the hole/cavity facing the flow: forwarddir [-1 0 0] v 50 np 8

Screenshot, I stopped quickly @ 12%

Regards, Julien