Some experiments in partially dissociated boundary layers

A series of flat-plate laminar boundary layer experiments carried out in an arc-heated supersonic wind tunnel is described. Measurements of the static pressure distribution, the total pressure profiles through the boundary layer, and the heat-transfer rates to catalytic and non-catalytic surfaces at moderately high enthalpies are given and compared with various theoretical predictions. The observations indicate that the dissociation fraction affects the boundary-layer profiles through its influence on the local transport properties. It is confirmed that the atomic recombination at the surface is retarded by using a non-catalytic oxide coating, and hence the heat transfer to the wall is reduced.