Transitional regime control in a fully developed channel flow

Abstract

Friction drag reduction is one of the main topic of investigation because of the great beneficial fallout in different engineering field. Laminar transition can be efficiently controlled using suitable flow control techniques [1]. Recent studies focused on the possibility of controlling transitional regimes in wall bounded flow have shown that the generation of streaks with appropriate intensity are able to control the transition in boundary layer. The concept of such control was shown by A1 et al. [2] using small cylinder mounted in the spanwise direction of a flat plate a zero incidence. These devices were able to generate streamwise vortices that in turn gave rise to streaks of well specific amplitude able to attenuate the transition. The paper will present results of an experimental investigation related to the transition control in a fully developed channel flow. For the streaks generation couples of convergent jets are positioned in the spanwise direction. In figure 1 the channel with the injection system are shown