Accession Number : ADA136921

Title :   The Effect of Trailing Vortices on the Production of Lift on an Airfoil Undergoing a Constant Rate of Change of Angle of Attack.

Descriptive Note : Master's thesis,


Personal Author(s) : Tupper,K W

PDF Url : ADA136921

Report Date : Dec 1983

Pagination or Media Count : 81

Abstract : The purpose of this study was to investigate the effect a trailing vortex wake has on an airfoil undergoing a constant rate of change of angle of attack, alpha, in two-dimensional, incompressible, irrotational flow. Potential flow theory, conformal mapping by the Joukowski transformation, and numerical integration and differentiation techniques were used to develop a computer algorithm to model the problem. Once the program was formulated, it was used to solve the impulsive-start problem of airfoil motion. The results were found to be in excellent agreement with the results obtained by others. When applied to the constant rate-of-change of angle-of-attack problem, the results showed that a trailing vortex wake has a measurable and predictable effect on the production of lift on an airfoil undergoing a constant alpha. While results of this work, taken alone, are helpful in understanding the phenomena known as dynamic stall, coupled with existing boundary-layer studies the results may lead to additional understanding of the phenomena. More specifically, the computer program develop here could be used to predict more realistically the inviscid flow about a pitching airfoil as it approaches the dynamic-stall conditions.

Descriptors :   *Lift, *Wake, *Airfoils, *Trailing vortices, Angle of attack, Incompressible flow, Two dimensional flow, Variations, Constants, Rates, Boundary layer, Potential flow, Flow fields, Pitch(Motion), Camber, Thickness, Conformal mapping, Transformations(Mathematics), Coefficients, Algorithms, Numerical integration, Computer programs, Inviscid flow, Mathematical prediction, Theses

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE