Vortex flow

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This is a vortex, in wind, above a floor.

Instead of blowing with the wind, the vortex stands still, due to a ground effect, wherein it sees its own mirror image in the ground, which try to rotate the vortex in the opposite direction of the wind, resulting in it standing still.

Click on it to make stuff happen.

This simulation uses semi-Lagrangian calculations.

Put here 2010.01.20 by Kim yhus (c)