Hybrid Large-Eddy Simulation/Reynolds-Averaged Navier-Stokes Methods and Predictions for Various High-Speed Flows

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Title: Hybrid Large-Eddy Simulation/Reynolds-Averaged Navier-Stokes Methods and Predictions for Various High-Speed Flows
Author: Boles, John Arthur
Advisors: Jack Edwards, Committee Chair
Hassan Hassan, Committee Member
Hong Luo, Committee Member
Fred DeJarnette, Committee Member
Abstract: Hybrid Large Eddy Simulation/Reynolds-Averaged Navier-Stokes (LES/RANS) simulations of several high-speed flows are presented in this work. The solver blends a Menter BSL two-equation model for the RANS part of the closure with a Smagorisnky sub-grid model for the LES component. The solver uses a flow-dependent blending function based on wall distance and a modeled form of the Taylor micro-scale to transition from RANS to LES. Turbulent fluctuations are initiated and are sustained in the inflow region using a recycling/rescaling technique. A new multi-wall recycling/rescaling technique is described and tested. A spanwise-shifting method is introduced that is intended to alleviate unphysical streamwise streaks of high- and low-momentum fluid that appear in the time-averaged solution due to the recycling procedure. Simulations of sonic injection of air, helium and ethylene into a Mach 2 cross-flow of air are performed. Also, simulations of Mach 5 flow in a subscale inlet/isolator configuration with and without back-pressuring are performed. Finally, a Mach 3.9 flow through a square duct is used as an initial test case for the new multi-wall recycling and rescaling method as well as a multi-wall shifting procedure. A discussion of the methods, implementation and results of these simulations is included.
Date: 2009-10-02
Degree: PhD
Discipline: Aerospace Engineering
URI: http://www.lib.ncsu.edu/resolver/1840.16/3428


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