Date of Award

Summer 1987

Document Type


Degree Name

Doctor of Philosophy (PhD)


Mechanical & Aerospace Engineering


Mechanical Engineering

Committee Director

Robert L. Ash

Committee Member

F. J. Brock

Committee Member

James N. Moss

Committee Member

S. N. Tiwari

Committee Member

Linda Vahala


Hypersonic transitional flow has been studied using the Direct Simulation Monte Carlo method. The cylindrically blunted wedge and spherically blunted cone were examined for body half angles of 0°, 5° and 10°, at a flight velocity of 7.5 km/s, zero angle of incidence and altitudes of 70 to 100 km. Those geometries and flow conditions are important considerations for hypersonic vehicles currently under design. Surface chemistry was examined for diffuse, finite-catalytic surfaces. Nonequilibrium chemistry and nonequilibrium thermodynamics were considered for both configurations at all altitudes.

Numerical simulations showed that rarefied gas effects, such as surface temperature jump and velocity slip, exist. Slip conditions were more significant for the axisymmetric cases and the onset of chemical dissociation occurred first for the two-dimensional configuration at 96 km. Comparisons between the numerical simulation and viscous shock-layer calculations at the higher altitudes show significant differences in the calculated heat-transfer rate, body drag and flowfield structure. A comparison with hypersonic wind tunnel heat-transfer rate data showed good agreement.