“FLUID ROLLER BEARING” EFFECT AND FLOW CONTROL

Owing to the rapid development of smart materials, flow control by travelling waves (TW) produced on flexible skin is becoming a very promising new area of research. One of the most revolutionary concepts of using TW technique is to trap a row of controllable vortices over the body surface, which plays a role of “fluid roller bearing” (FRB) between the external flow and the solid wall. The FRB can replace the conventional boundary layer and hence remove the latter‘‘s various unfavorable effects. This paper reports our preliminary numerical study of the FRB effect on flow over several typical walls, especially an airfoil with FRB at the stall angle of attack, which has never been considered before. Significant improvement of aerodynamic performance on the FRB-airfoil is observed, which strongly suggests that the FRB effect may open a brand new avenue to the 21th-Century aerodynamics.