Dissertation/Thesis Abstract

Detection of Boundary Layer Separation and Implementation of Autonomous Vortex Generators
by Morice, Samuel Davis, M.S., University of California, Davis, 2019, 79; 27539485
Abstract (Summary)

Boundary layer separation is a physical phenomenon that can result in aircraft stall, which is responsible for many fatal airplane accidents. This research aims at designing a boundary layer separation detection system that could be added on new aircraft or retrofitted on existing aircraft. This detection system was designed, fabricated, and used to demonstrate an autonomous vortex generator system that detects boundary layer separation in real-time and activates vortex generators to delay the boundary layer separation. The system uses flush-mounted microphones to detect an increase of acoustic power in the low-frequency range of pressure fluctuations indicating incipient separation. Vane-type vortex generators are aligned with the flow until the microphones detect separation. The vortex generators are then rotated to an angle of attack at which they produce vortices that delay boundary layer separation.

Wind tunnel tests are performed with a 2D wing with a NACA 0012 airfoil at chord Reynolds numbers of 500,000 and 1,000,000 in order to characterize the boundary layer’s frequency domain over a range of angle of attack that includes stall. Results show that the microphones are effective at detecting boundary layer separation and can be used to activate vortex generators. The active vortex generators are shown to increase maximum CL 13.8% and 6.9% for Reynolds numbers of 500,000 and 1,000,000 respectively when compared to maximum CL of the clean wing.

Indexing (document details)
Advisor: Robinson, Stephen K
Commitee: van Dam, C P, Baughn, James
School: University of California, Davis
Department: Mechanical and Aerospace Engineering
School Location: United States -- California
Source: MAI 81/8(E), Masters Abstracts International
Subjects: Aerospace engineering, Fluid mechanics, Mechanical engineering
Keywords: Boundary layer separation, Stall control, Viscous fluid dynamics
Publication Number: 27539485
ISBN: 9781658412698
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