Flow Field Over Boat-Tail Region of Heat Shield of a Typical Launch Vehicle at Mach 2

Abstract

Boat-tailed heat shields offer a higher payload volume but lead to flow separation and associated effects. In the present paper an attempt is made to find out the effect of boat-tail angle on the over all flow field with special emphasis on acoustic load near the boat-tail region. Experiments and CFD routes are used to investigate the flow field. Experiments consist of steady and unsteady pressure measurements and flow visualisation through schlieren and oil flow. CFD simulations are also carried out for the wind tunnel conditions. Results indicate that fluctuating pressure co-efficient increases with flow separation, peaks at reattachment point and reduces further downstream. An Increase in boat-tail angle from 20" to 30" leads to about I2Vo increase in acoustic load-s. All these studies were carried out at a Mach number of 2 and a Reynolds number of 4 x t}o based on model length.