Hi, I was wondering if there are certain techniques tosimulate a boundary layer between water and air. I would like todetermine drag and lift forces of the hull of an amphibian aircraftplaning on the water, just before lift-off. I placed the model ofthe aircraft in an assembly file where the top plane represents thesurface of the water. I used the assembly cut extrude feature toremove everything above the top plane so that only the portion ofthe hull in the water remains. I set Analysis Type to External,Fluids to Water, Velocity in Z direction to 88 ft/s, Global Goalsto Y and Z Component of Force, and Computational Domain Y max to 0ft to represent the surface of the water.
After some investigation I realized the horizontal forces seemedfar too high, the vertical forces were negative and that the waterflow seemed to be crossing the top plane.
I then created a simple extrusion to represent the air andspecified the bottom face as an ideal boundary wall condition. Thiscorrected the flow lines of the water but the forces still do notmake sense.
What else needs to be set up for a proper determination of dragforce?

Thanks,
Peter FerreiraSolidworksFlow Simulation