Faculty Advisor or Committee Member

William W Durgin, Advisor

Faculty Advisor or Committee Member

David J Olinger, Committee Member

Faculty Advisor or Committee Member

Homer F Walker, Committee Member

Faculty Advisor or Committee Member

Yiming Rong, Committee Member

Co-advisor

Gretar Tryggvason

Identifier

etd-042607-093941

Abstract

Direct Numerical Simulation of channel flow was utilized to study the evolution of various vortex configurations presented as flow initial conditions. Simulations of longitudinally, laterally and cross-flow oriented vortices suggested that the predominant form of turbulent structure was the half hairpin vortex. This vortical structure was dominant in the simulations seen in this as well as other investigations. In all cases hairpin vortices quickly degenerated to half hairpin or inclined vortical structures. It is hypothesized that these structures function as the predominant momentum transfer mechanism within the boundary layer, entraining fluid into the vortex cores like miniature tornados and transporting this fluid to the top of the boundary layer while simultaneously dragging fluid viscously around the inclined core of the vortex causing mixing of low-speed and high-speed flows.

Publisher

Worcester Polytechnic Institute

Degree Name

PhD

Department

Mechanical Engineering

Project Type

Dissertation

Date Accepted

2007-04-26

Accessibility

Unrestricted

Subjects

mixing length, vortical structure, Turbulence, Vortex-motion, Turbulence, Boundary layer

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