Theses and Dissertations

Radwa Alaziz

Issuing Body

Mississippi State University

Advisor

Sescu, Adrian

Committee Member

Belk, Davy M.

Committee Member

Janus, J. Mark

Date of Degree

12-8-2017

Document Type

Graduate Thesis - Open Access

Major

Aerospace Engineering

Degree Name

Master of Science

College

James Worth Bagley College of Engineering

Department

Department of Aerospace Engineering

Abstract

Görtler vortices develop in boundary layer flows over concave surfaces due to the imbalance between centrifugal forces and the wall-normal pressure gradient. These vortices can be efficient precursors to transition in boundary layers exposed to free-stream disturbance or surface non-uniformities, because they can alter the mean flow causing the laminar flow to breakdown into turbulence. In this thesis, a control technique aimed at reducing the energy associated with Görtler vortices that develop in supersonic boundary layers is introduced and tested. The control algorithm is based on distributed blowing and suction, with sensors placed either in the flow or at the wall. The result show that there is a dependence between the efficiency of the control algorithm and the spanwise separation of the vortices, that is the energy reduction is more significant for larger spanwise separations. The efficiency of the control algorithm seems to be insensitive to the variation of the Mach number.

URI

https://hdl.handle.net/11668/18533

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