Turbulence budgets in oblique shockwave/turbulent boundary layer interactions

In high-speed aerodynamics, shockwave/turbulent boundary layer interactions (STBLIs) can be responsible for design-limiting thermal and pressure loads (Dolling 2001). Additionally, when experienced in the inlet/isolator systems of ramjets and scramjets, separation and flow unsteadiness caused by STBLI can lead to additional blockage effects which may affect operability margins to engine unstart (Wagner et al. 2009). It is unclear, however, how accurately STBLIs, which have been shown experimentally to experience low-frequency unsteadiness (Dolling & Murphey 1983), can be captured with Reynoldsaveraged Navier-Stokes (RANS) computations (Settles et al. 1979; Zheltovodov 2004). It is therefore the objective of the present work to explore the physics of oblique STBLI with high-fidelity large-eddy simulation (LES) and to present accurate descriptions of the turbulence budgets for a variety of interactions with different shock strengths and Reynolds numbers. It is our hope that this information can then be used to better inform reduced-order models such as RANS for predictions of STBLI phenomena. Previous work by our group (Morgan et al. 2011a) has presented and established confidence in our LES database of oblique STBLI simulations by comparison with direct numerical simulation (DNS) by Pirozzoli & Bernardini (2011) and experimental particle image velocimetry (PIV) by Piponniau et al. (2009). In the present work, we build upon our previous results by compiling turbulence budgets for seven different shock strengths (achieved by varying the shock-generating wedge angle between 6.5◦ and 9.5◦) with baseline results at two different Reynolds numbers (Reθ = 1500, 2300). In section 2, we begin by presenting a brief discussion of the mathematical formulation, numerical schemes, and flow conditions used in the present study. In section 2.3, the cause and effect of numerical dissipation in our numerics is investigated in some detail, and in section 2.4, we validate our baseline budget by comparison with DNS results by Pirozzoli & Bernardini (2011). Then, in section 3, we present the turbulence budgets extracted from our oblique STBLI database with parametric variation. Finally, in section 4, conclusions are drawn and recommendations are made regarding the direction of future research.