FLOW FIELD ANALYSIS OVER AERO-DISC ATTACHED TO BLUNT-NOSED BODY AT MACH 6

摘要

Aero- spike attached to a blunt body significantly alters its flow field and influences aerodynamic drag at high speeds. The dynamic pressure in the recirculation area is highly reduced and this leads to the decrease in the aerodynamic drag. Consequently, the geometry of the aero-spike has to be simulated in order to obtain a large conical recirculation region in front of the blunt body to get beneficial drag reduction. Axisymmetric compressible Navier-Stokes equations are solved using a finite volume discretization in conjunction with a multistage Runge-Kutta time stepping scheme. The effect of the various types of aerospike configurations on the reduction of aerodynamic drag is evaluated numerically at Mach 6 at a zero angle of attack. The computed density contours agree well with the schlieren pictures. Additional modification to the tip of the spike to get the different type of flow field such as formation of shock wave, separation area and reattachment point are examined, including a conical spike, flatdisk spike and hemispherical disk spike attached to the blunt body. Shock polar is obtained using the velocity vector plot. The bow shock distance ahead of the hemispherical and flat-disc is compared with the analytical solution and good agreement found between them. The influence of the shock wave generated from the spike, interacting with the reattachment shock is used to understand the cause of drag reduction.