One or more wind directions failing to converge on an urban CFD simulation

I’m currently working on a CFD simulation using Eddy3d CFD and I’m having issues. Whenever I run a multi-orientation simulation, 1 or 2 orientations have issues and crash.

Example 1. / Base case urban model without trees.

For this case, all the orientations went fine, except the 180 Degree orientation, this one failed after only 180 steps it crashed.


Compared with other orientations

Example 2. / Base case urban model with trees.

For the case with trees, 2 orientation is not working, namely (180 and 315 degrees)

Here are my Eddy settings


Pablo Arango

Hi Pablo,

Your geometry looks fairly clean, we definitely ran much more complex models successfully.

  1. Do you have layers turned on? If yes, I would try to turn them of and see if that helps. Layers are the right thing to do but be aware that your geometry needs to be especially watertight for you to not run into trouble.
  2. I would try to increase the refinement levels for the ground and buildings. Sometimes, cases that are too coarse become unstable because of random polygon clipping by snappyHexMesh that produces unintended consequences .