Date of Award

6-2020

Degree Name

MS in Aerospace Engineering

Department/Program

Aerospace Engineering

College

College of Engineering

Advisor

Paulo Iscold

Advisor Department

Aerospace Engineering

Advisor College

College of Engineering

Abstract

This study demonstrates the applicability of using a modified application strategy of panel method to analyze low aspect ratio wings at preliminary design phases. Conventional panel methods fail to capture the leading edge vortex (LEV) that is shed by wings with low aspect ratios, typically below 2 depending on planform. This aerodynamic phenomenon contributes to a significant amount of the lift of these wings and the result is a drastic underestimation of the lift characteristics when analyzed by conventional panel method. To capture the effect of the leading edge vortex, a panel method code was used with an extended definition of the Kutta condition along portions of the leading edge inducing a vortex to shed from the leading edge and flow aft just inside the leading edge. To validate that this method, it was applied to 2 elliptical planforms with constant thickness where experimental force balance data was available. Additionally, the same 2 wings were analyzed using a finite volume solver to compare pressure distributions and to demonstrate the difference in magnitude of solution times. For comparison purposes, the resulting forces and moments from both computational methods and experimental testing were plotted over a range of angles of attack. Overall, the results demonstrate that a modified panel method could be used during the preliminary design phases for low aspect ratio wings. The panel method can reasonably model the lift and induced drag characteristics of low aspect ratio wings. This method loses applicability beyond the stall point where the leading edge vortex breaks down and oversimplifies pitching moment relation to angle of attack. Additionally, when compared to finite volume solutions of the same scenario, the panel method provided a result 20 to 30 times faster than the finite volume solutions. With this in mind, the modified panel method application strategy lends itself to preliminary design phases of low aspect ratio wings where the level of detail does not warrant finite volume analysis and solution speed has higher priority.

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