Topology Optimization in an empty space without any wall

[chairmanmao256]

Hi! I'd like to carry out a Topology Optimization in an empty space without any wall. I've run a case of which the computational domain is rectangular and inout is used for boundary condition. However, DAFoam fails during mesh check before evaluating the objective function. All quantities related to mesh check (bounding box, min volume and so on) are nan. I checked pyDAFoam.py and it says that the designSurface must be a wall. Is there a way to do Topology Optimization in a computational domain with no wall boundary condition imposed? Or do I have to include at least one wall boundary for any optimization even if the design variable is a field?

Thank you!!!

[friedenhe]

Yes, you have to have at least one wall patch and set it as the design surface. If you do not have a wall, you have to hack pyDAFoam. This line:

dafoam/dafoam/pyDAFoam.py

Line 3083 in e49c736

if bc["type"] == "wall" or bc["type"] == "slip" or bc["type"] == "cyclic":

You need to change it to:

if bc["type"] == "wall" or bc["type"] == "slip" or bc["type"] == "cyclic" or bc["type"] == "patch":

[chairmanmao256]

Thanks a lot!!! I'll read the related code in pyDAFoam.py and give it a try!