Aerodynamic heating for gaps in laminar and transitional boundary layers

The presence of gaps, slots, and/or steps in a surface may significantly perturb a supersonic boundary layer. The paper discusses heat-transfer distributions for a variety of gap configurations which were obtained by placing instrumented inserts in a flat-plate structural carrier. The data were obtained in a 3.50 foot hypersonic wind tunnel at a freestream Mach number of 5.10 over a range of Reynolds number from 2,570,000 to 8,110,000. The variables of the test program included the freestream Reynolds number and the gap configuration, e.g., width, depth, step height, number, and orientation.