Base flow and exhaust plume interaction. Part 2

Abstract

A computational study of the flow field along an axi-symmetric body with a single operating exhaust nozzle has been performed in the scope of an investigation on base flow-jet plume interactions. Results of a single nozzle plume with a high supersonic exit Mach number of 4 exhausting in co-flowing supersonic free stream of Mach 2.98 are presented for a number of jet stagnation pressure to freestream static pressure ratios, ranging from Ptj/Poo = 600 to no-jet flow at Mach 2.98. These conditions were used to validate the numerical Euler and Navier-Stokes Simulations with experimentally obtained data [4, 14]. Euler and Navier-Stokes simulations have been made in combination with regular meshes. In order to obtain a better physical representation of the interaction zone mesh adaptation has been applied for a Navier-Stokes simulation. One-dimensional adaptation to the Mach number distribution has been applied along fixed lines in the radial direction. In this way the flow field could be accurately portrayed. The three numerical simulation techniques are compared using flooded Mach-number contour plots. The Navier-Stokes simulation with Mach-adapted mesh provided the basis tor comparison with experimental results. A physical description of the flow field in the base region, or cavity, is presented using streamlines. Reattachment of the flow to the base of the model, which results in heat-transfer to the surface, has been found to be possible at approximately 45% to 50% of the base radius, measured from the centerline. However, reattachment has not been accurately visualized. Base pressure distributions obtained through all three different types of numerical simulation are presented in order to compare to the experimental data. No proper reproduction of the experimental Pb/Poo - Ptj/Poo curve (see [4, 14] could be attained.