METHOD OF AND APPARATUS FOR INFLUENCING THE BOUNDARY LAYER OF A BODY EXPERIENCING PREDOMINANTLY STOCHASTIC FLOW FLUCTUATIONS

摘要

To influence the fluid flow (having flow velocity U0) in the boundary layer of a body over the surface 8 of which the flow passes for reducing resistance or preventing flow separation, during predominantly stochastic flow fluctuations the frequency of the flow is sensed by a sensor 1. The sensed value is passed to an analyzer control circuit 2 which, in turn supplies a signal to a vibration transmitter 3 for introducing a vibration into the fluid flow for either damping or amplifying the flow. A periodic vibration of the same frequency can be superposed on the predominant stochastic frequency. In an alternative arrangement (Fig. 1) a countersignal can be impressed on the original vibration at the same location where the original vibration is sensed.