Date of Award


Document Type


Degree Name

Master of Science in Astronautical Engineering


Department of Aeronautics and Astronautics

First Advisor

W. Jerry Bowman, PhD


The effects of localized aerodynamic heating in cylinder expansion gaps positioned in cross flow were investigated in a shock tube. For this study, Mach number and Reynolds number were varied from 1.04 to 1.38 and 5 x 105 to 9 x 105, respectively. The cylinder was instrumented with quick response time thermocouples positioned on the surface of the cylinder, the wall of the gap, and the gap floor. Gap aspect ratios varied from 1.23 to 3.69. Pressure gauges were used to measure wave shock speeds, pressure ratios, and transient pressure conditions. Surface temperatures were measured and converted to heat fluxes using a one-dimensional semi-infinite slab model. Adiabatic wall temperatures were obtained from pressure measurements and ideal gas law relationships. Local nondimensional heat transfer coefficients, Nusselt numbers, were calculated from experimental surface and adiabatic wall temperatures. The present study found a direct dependence on Nusselt number values with Mach number. Peak heating inside the gap was determined to be a function of gap width and location on the cylinder. As gap width was reduced, the location of peak heating on the cylinder varied and Nusselt number values on the floor of the gap dominated.

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