Influences of wall vibration on shock train structures and performance of two-dimensional rectangular isolators in scramjet engine

Abstract

Shock trains are formed by shock wave boundary layer interaction in isolator to match the pressure between inlet and combustor. However, the complexity of this problem has primarily restricted to rigid isolators without deformation. A little is known regarding the impact of wall vibration, due to structural elasticity, on the flow in isolator. The current study focuses on this problem by comparing changes of 13 parameters regarding separation zone, shock structure, flow asymmetry and isolator performance. Results examine the differences due to one-wall vibration, two-wall vibration and short panel vibration. Analyses indicate that one-wall vibration will cause the upstream movement and length decrease of separation zone, upstream movement and length growth of shock trains, increase of flow asymmetry with large transient side loads and decrease of performance. Moreover, compared to one-wall vibration, two walls vibrating in opposite direction leads to a larger influence on flow structures and isolator performance, while the effect of two-wall vibration in the same direction is relative minor on flow structures and significant on flow asymmetry as well as isolator performance. Furthermore, by placing vibrating panels at different locations, analyses identify that the influence of upstream and midstream vibrations is stronger than downstream vibration in wall vibration. The upstream vibration has a greater impact on flow structures while the midstream vibration has a greater effect on flow asymmetry and isolator performance. The current study emphasizes the importance of future investigations on aeroelastic problem in isolator and provides primary knowledge for flow control by considering flexible or vibrating panel.