Date of Award

12-2008

Degree Name

Master of Science in Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Dr. Tianshu Liu

Second Advisor

Dr. Parviz Merati

Third Advisor

Dr. Javier Montefort

Access Setting

Masters Thesis-Open Access

Abstract

This work describes the application of a global luminescent oil film skin friction meter to quantitative global skin friction diagnostics in complex separated flows. The development of this technique is based on the relationship between the oil film thickness and luminescent intensity of an oil film mixed with a luminescent dye. The projected thin oil film equation is given to relate the normalized luminescent intensity with skin friction. The basis for this technique is the variational solution for the thin oil film equation on the image plane. The variational formulation with a smoothness constraint on skin friction is proposed to obtain a snap shot solution from two consecutive images for a relative skin friction field. Then, a complete skin friction field is reconstructed through superposition of a sequence of snap shot solutions.

This technique is used to obtain normalized skin friction fields in junction flows for circular, square and diamond cylinders, flows over surface roughness elements, a low aspect ratio rectangular wing, a 65° delta wing, a 76/40° double-delta wing with juncture fillets, and a trailer tail plate. Detailed skin friction line, skin friction vector and skin friction magnitude plots are presented together with detailed analysis of the complex skin friction topology of each test subject.

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