Development of a New Boundary Layer Control Technique for Automotive Wind Tunnel Testing

*† Many different boundary layer control techniques are used in ground vehicle aerodynamic testing including suction, blowing, ground-boards, and rolling roads. In this paper an alternative boundary layer control method is discussed. Low momentum flow in the boundary layer can be energized using circulation from a rotating cylinder protruding through the floor. A comparison study shows that this application, if effective, may be a more cost-efficient solution than current road vehicle boundary layer control techniques. Furthermore, a boundary layer flow survey was conducted in the Wichita State University 7’x10’ wind tunnel as a baseline in order to conduct future proof-of-concept testing. The survey showed a displacement thickness growth from 1” at the test section entrance to 3” at the start of the diffuser. Testing in a pilot tunnel has also been completed with the results showing that a boundary layer profile with an initial momentum displacement thickness of 0.098 in. could be reduced by 40-45% with rotational velocities of approximately 5000rpm. The goal of this paper is to document a two week pilot study for this alternative boundary layer control technique to determine possible application to the 7’x10’ wind tunnel.