Year of Publication

2005

Document Type

Thesis

College

Engineering

Department

Mechanical Engineering

First Advisor

Raymond P. LeBeau

Abstract

Recent interest in Micro Aerial Vehicles (MAVs) and Unmanned Aerial Vehicles (UAVs) have revived research on the performance of airfoils at relatively low Reynolds numbers. A common problem with low Reynolds number flow is that separation is almost inevitable without the application of some means of flow control, but understanding the nature of the separated flow is critical to designing an optimal flow control system. The current research presents results from a joint effort coupling numerical simulation and wind tunnel testing to investigate this flow regime. The primary airfoil for these studies is a modified 4415 with an adaptive actuator mounted internally such that the camber of the airfoil may be changed in a static or oscillatory fashion. A series of simulations are performed in static mode for Reynolds numbers of 25,000 to 100,000 and over a range of angles of attack to predict the characteristics of the flow separation and the coefficients of lift, drag, and moment. Preliminary simulations were performed for dynamic mode and it demonstrates a definitive ability to control separation across the range of Re and AoA. The earlier experimental work showed that separation reduction is gradual until a critical oscillation frequency is reached, after which increases in frequency have little additional impact on the flow. Present numerical simulation results were compared with the previous experiments results which were performed on the airfoil in like flow conditions and these comparisons allow the accuracy of both systems to be determined.

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