Report Forces And Porous Jump

jkl

I am trying to simulate flow around a 2d section bridge, modeling fences and wind shields by means of porous jump. I want to know global aerodynamic forces acting on the body I'm studying, thus calculating forces also on the porous jump. By now I've been using a simple trick, but I would like to use a more reliable approach, anynone can tell me ??

Thanks In Advance,

jkl.