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Hybrid large-eddy simulation/Reynolds-averaged Navier-Stokes methods and predictions for various high-speed flows

Posted on:2010-01-01Degree:Ph.DType:Dissertation
University:North Carolina State UniversityCandidate:Boles, John AFull Text:PDF
GTID:1440390002977198Subject:Engineering
Abstract/Summary:
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 crossflow 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.
Keywords/Search Tags:Simulations
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