Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Newman III, James C.

Committee Member

Burgreen, Greg W.

Committee Member

Janus, J. Mark

Committee Member

Cinnella, Pasquale

Date of Degree

5-8-2004

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

A finite element solver has been developed for performing analysis and sensitivity analysis with Poisson's equation. An application of Poisson's equation in fluid dynamics is that of poential flow, in which case Posson's equaiton reduces to Laplace's equation. The stiffness matrix and sensitivity of the stiffness matrix are evaluated by direct integrations, as opposed to numerical integration. This allows less computational effort and minimizes the sources of computational errors. The capability of evaluating sensitivity derivatives has been added in orde to perform design sensitivity analysis of non-lifting airfoils. The discrete-direct approach to sensitivity analysis is utilized in the current work. The potential flow equations and the sensitivity equations are computed by using a preconditionaed conjugate gradient method. This method greatly reduces the time required to perfomr analysis, and the subsequent design optimization. Airfoil shape is updated at each design iteratioan by using a Bezier-Berstein surface parameterization. The unstrucured grid is adapted considering the mesh as a system of inteconnected springs. Numerical solutions from the flow solver are compared with analytical results obtained for a Joukowsky airfoil. Sensitivity derivaatives are validated using carefully determined central finite difference values. The developed software is then used to perform inverse design of a NACA 0012 and a multi-element airfoil.

URI

https://hdl.handle.net/11668/20737

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