Yonghua Yan

Graduation Semester and Year

2012

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Mathematics

Department

Mathematics

First Advisor

Chaoqun Liu

Abstract

An implicitly implemented large eddy simulation by using the fifth order bandwidth-optimized WENO scheme is applied to make comprehensive studies on ramp flows with and without control at Mach 2.5 and Re=5760. Flow control in the form of microramp vortex generators (MVG) is applied. The results show that MVG can distinctly reduce the separation zone at the ramp corner and lower the boundary layer shape factor under the condition of the computation. A series of new findings are obtained about the MVG-ramp flow including the three-dimensional vortex structure generated by MVG. The mechanism about the formation vortex ring structure and its interaction with shock wave at the ramp corner is deeply studied. Vortex rings strongly interact with the flow and play an important role in the separation zone reduction. It shows that the ring structure does not break down and keeps it topology after penetrating the strong shock wave and the oblique shocks is influenced a lot by the induced flow field from rings. The bump of the 3D shock wave surface is discovered and its mechanism is explained.

Disciplines

Mathematics | Physical Sciences and Mathematics

Comments

Degree granted by The University of Texas at Arlington

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