High-Pressure Shock Tunnel Experiments and CFD Calculations on Spike-Tipped Blunt Bodies

Abstract

The requirements for the design of a new short-range high-velocity missile are the drag reduction and the acquisition of correct information for the optoelectronic sensors embedded in the hemispherical nose. High angles of attack must be studied to fulfill the maneuverability requirements of present and future missiles. A supersonic missile generates a bow shock around its blunt nose leading to high surface pressure and temperature and, as a result, the development of high drag and the damaging of embedded sensors. Pressure and temperature on the hemispherical nose surface can be substantially reduced if an oblique shock is generated by a forward facing spike. Both the experiments and the computations are carried out to study the flowfield around threedimensional blunt bodies equipped with forward facing spikes for a large range of angles of attack at a Mach number of 4.5. A blunt body, a classical disc-tipped spike, a sphere-tipped spike and a biconical-tipped spike are studied. The experiments involve high-pressure shock tunnel investigations using the shock tube facility of ISL. The differential interferometry technique is used to visualize the flowfield around the different missile spike geometries. The differential interferogram pictures and surface pressure measurements are compared with numerical results. Numerical simulations based on steady-state 3D Navier-Stokes computations are performed in order to predict the drag, the lift and the pitching moment for the blunt body and for each spike-tipped missile. The computations allow to bring out the advantages of each spike geometry in comparison with the blunt body.