Date of Award

12-1990

Document Type

Thesis

Degree Name

Master of Science in Aeronautical Engineering

Department

Department of Aeronautics and Astronautics

First Advisor

Philip Beran, PhD

Abstract

The effects of thermal nonequilibrium on flows about blunt-bodies have not been studied numerically in isolation from chemical reactions. Typically, air is modeled as a perfect gas or as a chemically reacting mixture. In the former case, significant errors result at Mach numbers exceeding about 5. However, below Mach numbers around 8, the effects of chemical reactions are negligible. This study analyzes flow about a simple axisymmetric blunt-body at moderate hypersonic speeds (Mach numbers between 5-8). A first-order-accurate Roe scheme was used to compute solutions of the Euler equations assuming different gas models: perfect gas, thermal equilibrium, and thermal nonequilibrium. Equilibrium and nonequilibrium shock standoff distances deviated 10-15 percent from perfect gas calculations. Nonequilibrium solutions produced striking temperature and density gradients in the stagnation region with a unique hot spot near the shock.

AFIT Designator

AFIT-GAE-ENY-90D-17

DTIC Accession Number

ADA230356

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