Open-loop control of compressible afterbody flows using adjoint methods

Abstract : We present the theoretical study of a compressible afterbody flow in the subsonic regime. We use sensitivity analyses developed in the framework of the linear global stability theory to predict beforehand the effect of a steady bulk and wall forcing on the growth rate of linear global modes. The sensitivity functions are derived analytically using adjoint methods, and presented for the global mode responsible for the onset of a periodic regime. Our results show that the global mode is sensitive to momentum forcing along the separation line, or to a localized heating in the core of the recirculating bubble.