Effect of Gas Radiation in the Boundary Layer on Aerodynamic Heat Transfer

Table 1 is based on the foregoing analysis and is computed at a Mach Number of 2.4 for a supersonic wind tunnel with a 1atmosphere supply pressure and a 300°K. supply temperature, where the theoretical value of recovery factor based on freestream conditions is 0.869. It can be seen from Table 1 that the wedge is at a temperature higher than the value obtained from Prwhen calculated for the measuring surface of the flat plate. Consequently, the boundary layer in contact with the wedge is warmer than under zero heat-transfer conditions. The effects of this high temperature are felt downstream along the main part of the model, since the plate now attains thermal equilibrium with a boundary layer of higher temperature resulting in the measurement of erroneous recovery factors. This phenomenon must be considered when dealing with all flat-plate wind-tunnel models with laminar boundary layers. Though the above analysis assumes a thin plate with a solid metallic wedge of small angle which is insulated from the rest of the model, the same effects will be present in flat plates with different details of construction.