The flow in a wind tunnel needs to be as laminar as possible. You can treat a skydiver in free fall like stationary object placed in a laminar flowing fluid. THE VELOCITY OF THE FLOWING FLUID IS CONSTANT. Fnet=Fdrag+Fgrav=ma=0 The flow over the skydiver will form a boundary layer. Inside of this boundary layer is where you will see all of your turbulence (burble). Ik this is a 10yr old thread but im guessing you went with a laminar flow.!