Title page for ETD etd-11597-17952


Type of Document Dissertation
Author Walker, Don Gregory Jr.
Author's Email Address greg.walker@vt.edu
URN etd-11597-17952
Title Estimation of Unsteady Nonuniform Heating Rates from Surface Temperature Measurements
Degree PhD
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Scott, Elaine P. Committee Chair
Diller, Thomas E. Committee Member
Lin, Tao Committee Member
Ng, Fai Committee Member
Vick, Brian L. Committee Member
Keywords
  • inverse heat conduction
  • shock interactions
Date of Defense 1997-11-25
Availability restricted
Abstract
Shock wave interactions such as those that occur during atmospheric

re-entry, can produce extreme thermal loads on aerospace structures.

These interactions are reproduced experimentally in hypersonic wind

tunnels to study how the flow structures relate to the deleterious

heat fluxes. In these studies, localized fluid jets created by shock

interactions impinge on a test cylinder, where the temperature due to

the heat flux is measured. These measurements are used to estimate the

heat flux on the surface as a result of the shock interactions. The

nature of the incident flux usually involves dynamic transients and

severe nonuniformities. Finding this boundary flux from discrete

unsteady temperature measurements is characterized by instabilities in

the solution. The purpose of this work is to evaluate existing

methodologies for the determination of the unsteady heat flux and to

introduce a new approach based on an inverse technique. The

performance of these methods was measured first in terms of accuracy

and their ability to handle inherently ``unstable'' or highly dynamic

data such as step fluxes and high frequency oscillating fluxes. Then

the method was expanded to estimate unsteady and nonuniform heat

fluxes. The inverse methods proved to be the most accurate

and stable of the methods examined, with the proposed method being

preferable.

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