One-Way Response of a Flexible Panel to Shock Wave Boundary Layer Interaction

Abstract

Numerical simulations of two-way fluid-structure interaction (FSI) between the turbulent shock wave boundary layer interaction (SBLI) and flexible panel can be computationally prohibitive, mainly due to the cost of high-fidelity flow simulations, such as the large eddy simulations (LES). This work explores computationally efficient one-way FSI and oscillating inviscid shock impingement frameworks in the context of SBLI over a flexible panel. In one-way FSI, a flexible panel is subjected to SBLI without any feedback of the structural deformation to the SBLI. The flow is at Mach 2.7 with the Reynolds number based on the inflow boundary layer thickness at Re_delta = 54, 600. To examine the one-way effect of a weak and a strong SBLI on the panel response, we consider two incident shock angles of 30.29 deg and 35.53 deg, which are engendered by the opposite surface inclinations of alpha_1 = 10.5 deg and alpha_2 = 15.7 deg, respectively, where the shock impinges at the mid-chord panel length location. The flexible panel has a length of a = 10.48 delta, an aspect ratio (width/length) of b/a = 1.3772, and a panel thickness of h/a = 0.003. At first, we examine the validity of one-way FSI by varying structural parameters, namely, the flutter parameter and the mass ratio, while the panel responds to an oscillating inviscid shock impingement, which produces SBLI-like forcing. This analysis indicates that the one-way FSI agrees well with two-way FSI panel response for lower values of the flutter parameter and mass ratio. At second, a flexible panel with lower values of the flutter parameter (lambda = 86) and mass ratio (m_r= 0.005) is subjected to turbulent SBLI, considering a weak and a strong interactions. In both cases, the oblique shock is strong enough (p_3/p_1 ≈ 3) to engender flow separation, in the time-mean sense, giving rise to characteristic low-frequency unsteadiness and turbulence amplification. The low-frequency dynamics of the SBLI at Strouhal numbers of St_delta = 0.03, 0.1, 0.14 (based on the flow separation length) appears to prominently instigate Mode(1,1), Mode(2,1), and Mode(3,1) of the panel response. Lastly, the oscillating inviscid shock impingement framework, which generates SBLI-like forcing on the flexible panel, leads to panel vibration that is in good agreement with the turbulent SBLI case.