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STABILITY OF THE COMPRESSIBLE LAMINAR BOUNDARY LAYER
CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS
Temperature fluctuations have a profound influence on both the inviscid slowly-varying and viscous disturbances above a Mach number of about 2.0. This analysis includes the effect of temperature fluctuations on the viscosity and thermal conductivity, and also introduces the viscous dissipation term that was dropped. Instead of being nearly constant across the boundary layer the amplitude of the inviscid pressure fluctuations decreases markedly with distance outward from the plate surface for Mach numbers greater than 3. This behavior means that the Reynolds shear stress near the critical layer is greatly reduced. At Mach numbers less than 2 dissipation effects are minor, but they become extremely important at higher Mach numbers and tend to become the dominant effect for hypersonic Mach numbers. The rate of conversion of energy from the mean flow to the disturbance flow through the action of viscosity at the wall increases with Mach number. The minimum critical Reynolds number for insulated flat plate boundary layers decreases in the range 0 less than or equal to M less than or equal to 3, and then rises very sharply for hypersonic Mach numbers. Author