ON INSTABILITY WAVE CONTROL IN TURBULENT JETS

The presentation is based on two main results obtai ned in the framework of international projects OPENAIR and ORINOCO. Two considered effects are determined by control of large scale structures in the initial part of shear layer. In the first part we have studied experimentally how plasm a actuators operating on the basis of surface barri er high frequency discharge affect jet noise characteristics (1). An actuator's effect on the jet in the applied configu ration is related to acoustic discharge excitation and to a large extent is simil ar to the well-known Vlasov-Ginevsky effect. Thus, the results of investigations of air jets (100-200 m/s) have demon strated that jet excitation in the case of St ~ 0.5 using the barrier discharge plasma actuator leads to broadband amplif ication of jet sound radiation. The jet excitation in the case of St > 2 leads to broadband noise reduction if the action is sufficiently intensive (Fig. 1).