Shock Wave Formation and Aerodynamic Heating in the Presence of a Protrusion on Flat Plate in High Speed Flow

Protruding objects from the surface of space orbiters induce aerodynamic heating at transonic to hypersonic speeds. The gap-filler material which came loose from between the insulation tiles on the surface of the space orbiter Discovery during its reentry is a case in point. The interaction between the protruding gap filler and the boundary layer may drastically alter the flow field at high speeds, resulting in formation of shock waves and aerodynamic heating of the walls. A CFD was carried out on a two-dimensional model of the flow over a gap-filler like protrusion attached to a flat wall representing the obiter surface. The flow was at speeds corresponding to three different orbiter Mach numbers of 2.54, 1.5 and 0.64 depending on the altitude. The flow and temperature fields were solved numerically. The computations indicated the formation of shock waves upstream and downstream of the gap filler and higher wall temperatures were noticed due to viscous dissipation effects. The maximum wall temperature at Mach number of 2.54 was 231°C, indicating 282°C overheating above the free stream temperature at an altitude of 25 km. Analysis of the results indicated the serious thermal impact of protruding objects on surfaces in high speed flow.