Computational study of a conceptual re-entry vehicle's aerodynamic characterization at Mach number-2

Abstract

Re-entry vehicles are becoming an important topic of study in recent times due to the interest of many countries in space endeavor. They are incorporated with double-delta wings having many profiles, different strake and wing swept angles. A conceptual re-entry vehicle having a double delta wing with NACA0020 symmetrical aerofoil at the top surface and the reflex aerofoil at the bottom is studied. Here, the main objective is to examine the effect of viscosity on the aerodynamic characteristics of the vehicle by varying the angle of attack from 10°to 50°at a free stream Mach number of 2. The steady-state Reynolds Averaged Navier-Stokes equations with Spalart-Allmaras turbulence model and Euler equations are solved using ANSYS Fluent for examining the contribution of the viscous term on flow past the re-entry vehicle. The non-dimensional coefficients of lift, drag, pressure, Mach number, and density gradients obtained from both the models are compared. It is observed that the coefficients of lift and drag obtained from Euler simulations differed significantly from the Spalart-Allmaras turbulence model at all angle of attacks. The maximum value of lift coefficient is seen at 40°in Euler simulation and it appeared at 35°in Spalart-Allmaras model. Both the models have predicted the zones of attached flow, separated flow, leading-edge vortices and the shock pattern over the vehicle. But the flow transition and vortex breakdown are observed earlier in Spalart-Allmaras model compared to inviscid simulations. It suggested that the viscosity and fluctuation in the upstream flow has a significant role in the aerodynamic characteristics of re-entry vehicles.