KFm-4 Fluid Simulation

Some fluid simulations over a KFm-4 airfoil using Blender. What I’m looking for is what’s going on behind those steps. Does a vortex or somekinda airbubble form? Using vectors you can clearly see that some of the particles behind the step go against the airflow over the wing. For more info about the airfoil tested see: –Fogleman_airfoil