Computation of three - dimensional transonic flow fields over a three - body launch vehicle configuration for low angle of attack conditions

Abstract

The present work aims at the prediction of shock wave position on the heat shield region of a three body launch vehicle in transonic region. The launch vehicle consists of a cylindrical core body and two boosters. The core body is made of a spherical nose, followed by a cone and heat shield region which is a flat surface. The heat shield is followed by a boat tail. Simulations are performed with commercial CFD package, ANSYS –FLUENT. Reynolds stresses are computed using the k-ω SST turbulence model. Explicit time integration is used to obtain steady-state solutions. A structured grid over the vehicle is generated using ICEMCFD software. In the near-wall region of the launch vehicle fine mesh is employed to capture the boundary layer. Simulations are performed for angle of attacks (AOA) 0° and 4° for Mach number 0.95. The computed nose stagnation pressure compared with the isentropic relations and deviation found to be .067%. A standing normal shock wave is observed for AOA 0 whereas an oblique shock wave is observed for angle of attack 4°. The predicted flow structure in terms of density distribution is compared with experimental schlieren images. The predictions captured essential flow features such as expansion around the conical part, boundary layer over the heat shield, shock wave on the heat shield, and flow separation in the boat tail region. The predicted flow structure and shock wave position for AOA O matched well with the experiments. However, for AOA 4°, the deviation between flow structure and shock position is noticed. Possible reasons for the deviation are explained.