Experimental and Numerical Investigations of SBLI and Flow Control on a Transonic Compressor Cascade

Abstract

The flow through a transonic compressor cascade is inherently unsteady due to the shock-boundary layer interactions (SBLI) on the blade. Despite decades of research, few details are known about the mechanisms that cause such behavior. This chapter presents a multidisciplinary study aiming to elucidate these mechanisms and optimize flow control methods to mitigate their effects. For this purpose, the Transonic Cascade TEAMAero was first optimized and its performance was validated experimentally. The cycle of shock oscillation was then compared using advanced experimental measurement techniques and high-fidelity LES. This comparison revealed a continuous propagation of pressure waves from a point upstream of the trailing edge. The interaction of these waves with the main bow shock at different points of the cycle was then linked to the frequencies observed in the oscillation spectrum. A configuration of this cascade with two roughness patches was finally optimized using a novel procedure developed. The optimal configurations obtained show how the targeted design of these devices can simultaneously mitigate shock oscillations and improve performance. This chapter demonstrates how the combined application of advanced numerical and experimental techniques needs to be intensified as researchers search for a global theory of SBLI in compressor blades.