Degree Type

Dissertation

Date of Award

1994

Degree Name

Doctor of Philosophy

Department

Aerospace Engineering

First Advisor

Alric P. Rothmayer

Abstract

A time accurate compressible interactive boundary layer procedure for airfoils using the quasi-simultaneous method of Veldman is developed. It couples the high frequency transonic small disturbance equation with the complete set of unsteady compressible boundary equations in Levy-Lees variable form, using a pseudo-time derivative of displacement thickness for enhanced stability. Included is a simple procedure for time accurately updating the viscous wake location. The basis of the interaction is an extension of the asymptotic matching condition of Davis for unsteady compressible interaction. This analysis identifies several possible unsteady transonic separation structures and highlights the importance of the pseudo-time derivative in stabilizing the interaction. The method is applied to oscillating airfoils experiencing light shock-induced stall. Comparisons are made with several standard turbulence models. Shock-induced oscillatory flow about the 18% circular arc airfoil is investigated with this method and found to be modeled quite accurately.

DOI

https://doi.org/10.31274/rtd-180813-9798

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Robert Edwin Bartels

Language

en

Proquest ID

AAI9424195

File Format

application/pdf

File Size

199 pages

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