NUMERICAL SOLUTIONS FOR RADIATING HYPERVELOCITY BOUNDARY LAYER FLOW ON A FLAT PLATE
Abstract : The effects of thermal radiation on laminar, flat plate boundary layer flow have been investigated. Non-similar velocity and temperature profiles were obtained as numerical solutions of an appropriate set of finite difference equations. Simplified expressions for the thermodynamic and transport properties were used together with a mean radiation absorption coefficient approximating that of air. On the basis of the results of a previous approximate analysis, it was assumed that the boundary layer would be optically thin; for the velocity range considered (10 to 40 km/s) the numerical results confirmed this hypothesis. It was found that the maximum temperatures in the radiating boundary layers were much lower than in the corresponding non-radiating cases and that the radiating boundary layers were much thinner. Changing the exponent in the temperature-viscosity relationship mu proportional to T to the omega power from 1.0 to .75 had a negligible effect on the maximum temperature in the boundary layer but caused a significant reduction in its thickness and thus in the radiative heat flux to the wall. The predictions of the approximate analysis were compared with the numerical results and found to give useful engineering estimates of the properties of radiating boundary layers. (Author)