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Numerical simulation of a plane turbulent mixing layer, with applications to isothermal, rapid reactionsA hybrid method has been developed for the numerical prediction of turbulent mixing in a spatially-developing, free shear layer. Most significantly, the computation incorporates the effects of large-scale structures, Schmidt number and Reynolds number on mixing, which have been overlooked in the past. In flow field prediction, large-eddy simulation was conducted by a modified 2-D vortex method with subgrid-scale modeling. The predicted mean velocities, shear layer growth rates, Reynolds stresses, and the RMS of longitudinal velocity fluctuations were found to be in good agreement with experiments, although the lateral velocity fluctuations were overpredicted. In scalar transport, the Monte Carlo method was extended to the simulation of the time-dependent pdf transport equation. For the first time, the mixing frequency in Curl's coalescence/dispersion model was estimated by using Broadwell and Breidenthal's theory of micromixing, which involves Schmidt number, Reynolds number and the local vorticity. Numerical tests were performed for a gaseous case and an aqueous case. Evidence that pure freestream fluids are entrained into the layer by large-scale motions was found in the predicted pdf. Mean concentration profiles were found to be insensitive to Schmidt number, while the unmixedness was higher for higher Schmidt number. Applications were made to mixing layers with isothermal, fast reactions. The predicted difference in product thickness of the two cases was in reasonable quantitative agreement with experimental measurements.
Document ID
19870035224
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Lin, P.
(Washington Univ. Seattle, WA, United States)
Pratt, D. T.
(Washington, University Seattle, United States)
Date Acquired
August 13, 2013
Publication Date
January 1, 1987
Subject Category
Fluid Mechanics And Heat Transfer
Report/Patent Number
AIAA PAPER 87-0224
Accession Number
87A22498
Distribution Limits
Public
Copyright
Other

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