Control of Cowl-Shock/Boundary-Layer Interactions by Deformable Shape-Memory Alloy Bump

Abstract

A deformable shape-memory alloy (SMA) bump is introduced to control the succeeding cowl-shock/boundary-layer interactions in a supersonic inlet with an operating Mach range of 2.0–3.8. The deformation characteristics and the control effect of the SMA bump are investigated by both experimental and numerical methods. It is found that the well-trained SMA bump can achieve the desired bump shape automatically. The total root mean square error between the actual SMA plate profile and the designed one is 0.05 times of designed bump’s height without aerodynamic load, whereas the value increases to 0.09 times of designed bump’s height at the end of the wind tunnel test. When the inlet operates at Mach 3.8 the shock-induced large separation is reduced substantially and transformed into two small-scale separation bubbles under the control of the deformable bump. The total pressure recovery of the bump controlled inlet is always higher than the uncontrolled one in the same back pressure ratio during the throttling process. The critical back pressure ratio of the controlled inlet reaches to 28, whereas the corresponding value of the uncontrolled inlet is only 23.