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Improvements to an Explicit Algebraic Stress Model for Turbulent Jet Mixing PredictionsModifications to key coefficients in a k − E based explicit algebraic stress model (EASM) are examined with the objective of improving the prediction of turbulent jet flows. The pressure strain coefficient, C2 and the turbulent diffusion coefficients, σk and σE were investigated. For a series of benchmark subsonic jets at heated and unheated conditions, lowering C2 from the default value of 0.36 to 0.10 resulted in a significant improvement in the jet mixing, when compared to experimental data. Changing σk and σE from default values of 1.00 and 1.4489, respectively, to 0.50 and 0.7244, respectively, improved the initial mixing rate, while reducing the farfield mixing rate and the peak turbulent kinetic energy along the centerline. A high-speed mixing layer was also investigated for performance of baseline and modified EASM coefficients, with similar results as for the jet cases. A flat plate boundary layer was briefly examined to determine the effects of changing the coefficients on the turbulent skin friction coefficient. The change to the pressure strain coefficient, C2 = 0.10 is recommended for future EASM calculation of jets flow; however, it is also recommended that the diffusion coefficients remain at their default values.
Document ID
20190004931
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Georgiadis, Nicholas J. (NASA Glenn Research Center Cleveland, OH, United States)
Yoder, Dennis A. (NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
May 2, 2019
Publication Date
March 1, 2019
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
NASA/TM—2019-219978
E-19661
AIAA Paper 2019–0325
GRC-E-DAA-TN65223
Meeting Information
Meeting: 2019 Science and Technology Forum (SciTech)
Location: San Diego, CA
Country: United States
Start Date: January 7, 2019
End Date: January 11, 2019
Sponsors: American Institute of Aeronautics and Astronautics (AIAA)
Funding Number(s)
WBS: 109492.02.03.01.05.01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Technical Review
Single Expert
Keywords
Turbulent Mixing
Algebraic Stress Model

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