| 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. A pilot tunnel test was performed in the WSU Boundary Layer Tunnel with the results showing a boundary layer profile with an initial momentum thickness of 0.098 in. could be reduced by 40-45% with rotational velocities of approximately 5000rpm. Following this successful test, a full scale test performed in the WSU Walter H. Beech Memorial Wind Tunnel demonstrated the feasibility of the concept. An initial momentum thickness of 0.1445 in. was reduced 29% with a rotational velocity of 3900rpm. The results found seem to indicate this technique would be a very viable option provided certain aspects including cylinder balance, sizing, and rotational velocity could be optimized in future testing. |
