The Role of Boundary-Layer Thickness on Cylinder- Generated Shock-Wave/Turbulent Boundary-Layer Interactions, Part I: Computations

摘要

Scaling parameters of a shock-wave/turbulent boundary-layer interaction generated by a semi-infinite standing cylinder were explored using steady-state RANS simulations. The simulations were performed in collaboration with an experimental study (see Part II) conducted at Mach 2.0. By maintaining constant Mach and Reynolds numbers, only the primary variable d, the cylinder diameter, and the secondary variable S, the boundary-layer thickness, were varied. The ratio of d/δ was varied from 0.125-16 via a constant set of d and δ to provide a broad range of values. A power law dependence on d/δ was observed for separation distance and triple-point height, which was verified by the experimental study and aligned with data from the literature. The impact of viscous effects on the shock orientation and interaction strength was found to increase in importance as the shock generator approached the scale of the boundary-layer thickness; conversely, for values of d/δ ≥ 6, the curvature and strength of the lambda-shock structure became seemingly independent of d/δ. Additionally, the viscous impact was observed for separation distance and triple-point height, where it correlated with a larger interaction scale, as well as a reduced peak pressure ratio on the floor upstream of the cylinder. The peak pressure ratio on the cylinder leading edge, however, only exhibited a dependence on d/δ for values less than 0.5. All cases exhibited a trough pressure ratio on the cylinder leading edge at y/d = 0.3, corresponding to a separation line of a secondary vortex. It appeared that this parameter was not a function of S.