RADIATING LAMINAR BOUNDARY LAYER FLOW OVER A FLAT PLATE AT A LARGE FREE-STREAM MACH NUMBER.

The problem of the laminar flow of a high temperature radiating gray gas parallel to an isothermal flat plate is considered. When the free-stream Mach number is large viscous heating inside the boundary layer affects the thermodynamic and thermophysical properties by changing them by several orders of magnitude. These changes show up by the presence of new physical details of flow. An asymptotic analysis of the radiationless problem using Kruskal's formalism essentially corroborates the deductions of the 'hypersonic interaction theory'. Also it forms the starting point for the radiating problem, Radiation Knudsen number, Boltzmann number and Mach number are the three parameters that enter the radiating flow. Differential approximation is employed for describing the radiation field. The Boltzmann number plays an important role in determining the effects and regimes of radiation interaction, and under certain limits shows details which closely resemble the flow for low Mach number. Solution to the problem is considered for the case of equal wall and free-stream temperatures and dominant radiation interaction in the weak shock limit. The interaction results in a general reduction of the temperature throughout the boundary layer, which itself is optically thin. The temperature field normalized with respect to the local maximum temperature shows similarity as a good approximation and is exploited to construct approximate solutions to the problem.