Date of Award

1997

Document Type

Thesis - Open Access

Degree Name

Master of Science in Aerospace Engineering

Department

Aerospace Engineering

Committee Chair

Allen I. Ormsbee

Committee Member

Tej R. Gupta

Committee Member

Eric v. K. Hill

Abstract

The purpose of this investigation was to determine the effects of biological fouling on hydrofoils. NACA 4412 and 4415 hydrofoil models with 6 inch chord and 8 inch span were used in this study. A water tunnel facility was designed and constructed to perform the tests, and the results were verified using computational fluid dynamic modeling. The CFD software package Fluent was used to create a two dimensional model of the water tunnel test section and hydrofoil. The model was meshed using a Laplacian grid smoothing technique that forced the structured grid lines to follow the same approximate contour as the stream lines, allowing for quicker convergence of the solution matrix and a lower degree of rounding error than normally associated with this type of modeling. The fouling was added to the model by introducing a porous medium on the surface of the hydrofoil to simulate the characteristics of biological fouling. The results showed a constant increase in zero-lift angle of attack by 10 degrees for as little as 10 percent fouling, and a reduction in maximum lift by as much as 80 percent.

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