Wall Suction on Laminar Separation Bubbles and Crossflow Instability of a Supersonic Finite-Span Swept Wing

This integrated study quantifies the suction intensity (Cq) effects on shock-induced laminar separation bubbles (LSBs) and crossflow instability on a supersonic finite-span 65° swept wing at a Mach number equal to 2 and a unit Reynolds number 3.29 × 107 m–1. Results demonstrate that low-strength suction (Cq < 0.01) triggers the LSBs through recompression-shock-induced adverse pressure gradients. Conversely, high-strength suction (Cq > 0.01) suppresses the LSBs by establishing sustained favorable pressure gradients. At the threshold Cq = 0.01, flow control is balanced: uniform N-factor distribution is maintained while crossflow instability growth is suppressed; beyond this threshold (Cq > 0.01), however, suction amplifies crossflow instability. These results resolve the trade-off between separation suppression and instability mitigation, establishing Cq = 0.01 as the optimal design parameter for crossflow instability delay in supersonic swept wings.