Effect of surface imperfections on the stability of compressible laminar boundary layers

The accuracy of the compressible interacting boundary-layer computations is investigated and their limitations are established by comparison with solutions to the Navier-Stokes equations both for the mean flow profiles and for the stability characteristics. The instabilities of flows around smooth forward and backward facing steps are investigated. Results presented include the effect of computational grid refinement, geometrical parametres such as heights and slopes of steps, Mach number and Reynolds number on the mean flow as well as the stability characteristics. A proper grid should be chosen to predict accurately the mean flow profiles, including their first and second derivatives. The study has shown that the heights of the steps are more influential in triggering transition than their slopes. Increasing the Mach number reduces the growth rates and amplification factors but the presence of small separation bubbles, which increase in size with increasing Mach number, partially offset this benefit.

Name thesis:degree_name

M.S.

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Engineering Science and Mechanics

Department dc:contributor.department

Engineering Science and Mechanics

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1988

Author dc:creator

• Krishna, R. C.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10919/109902

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/109902