An Analysis of Using Cfd in Conceptual Aircraft Design

An Analysis of Using CFD in Conceptual Aircraft Design
By Daniel J. McCormick

A Thesis Submitted to the Faculty of Virginia Polytechnic Institute and State University in Partial Fulfillment for the Degree of Masters of Science in Mechanical Engineering

Arvid Myklebust, Chairman

Paul Gelhausen

Sam Wilson

May 27, 2002 Blacksburg, Virginia

Keywords: CFD, Conceptual Aircraft Design, Lift, Drag, Farfield

An Analysis of Using CFD in Conceptual Aircraft Design By Daniel J. McCormick Committee Char: Arvid Myklebust Mechanical Engineering (ABSTRACT)

The evaluation of how Computational Fluid Dynamics (CFD) package may be incorporated into a conceptual design method is performed. The repeatability of the CFD solution as well as the accuracy of the calculated aerodynamic coefficients and pressure distributions was also evaluated on two different wing-body models. The overall run times of three different mesh densities was also evaluated to investigate if the mesh density could be reduced enough so that the computational stage of the CFD cycle may become affordable to use in the conceptual design stage. A farfield method was derived and used in this analysis to calculate the lift and drag coefficients. The CFD solutions were also compared with two methods currently used in conceptual design - the vortex lattice based program Vorview and ACSYNT. The unstructured Euler based CFD package FELISA was used in this study.

Contents
List of Figures List of Tables Nomenclature vii ix xi

1 Introduction 1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Issues with CFD Usage in Conceptual Design . . . . . . . . . . . . 1.2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.2 Surface Generation . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.3 Mesh Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.4 Computational Speed . . . . . . . . . . . . . . . . . . . . . ....