Pressure over a dual-cavity cascade at supersonic speeds

Pressure distributions over a dual cavity cascade were studied at supersonic speeds of Mach 1.5 and 2.5. The study was performed through numerical modelling and results compared with model measurements. The Reynolds-averaged Navier-Stokes equations were solved using a finite-volume algorithm in which the inviscid cell interface fluxes were estimated using Poe's approximate Riemann solver with a second-order extension, and turbulence was modelled using a two-equation k-omega model with compressibility corrections. Two test configurations were selected: (1) a length-to-depth ratio L/D = 1 cavity followed by another L/D = 1 cavity, and (2) an L/D = 3 cavity followed by an L/D = 1 cavity. The prediction was compared with that of a single cavity of the same L/D. It was found that the pressure field around the L/D = 1 cavity was substantially modified by a preceding L/D = 3 cavity, Changes in the pressure and pressure drag coefficient were observed. The study clarified some earlier observations of unsteady modes over a dual cavity cascade, and confirmed model measurements of the pressure fluctuation under a number of flow and geometry conditions.