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Effective forcing for direct numerical simulations of the shear layer of turbulent free shear flows

Dhandapani, Chandru and Rah, Kyupaeck Jeff and Blanquart, Guillaume (2019) Effective forcing for direct numerical simulations of the shear layer of turbulent free shear flows. Physical Review Fluids, 4 (8). Art. No. 084606. ISSN 2469-990X. https://resolver.caltech.edu/CaltechAUTHORS:20190828-092034904

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Abstract

A numerically efficient configuration to simulate turbulent flows is to use triply periodic domains, with numerical forcing techniques to sustain turbulence. Previous homogeneous shear turbulence simulations considered only idealized homogeneous shear flows and not the statistically stationary shear turbulence observed in practical free shear flows. In contrast, the current study mathematically derives the complete forcing technique from the large scales of the turbulent free shear flows. Different statistically stationary free shear flows are considered in this study, namely, a nearly homogeneous shear turbulent flow, turbulent mixing layer, a turbulent planar jet, and a turbulent round jet. The simulations are performed on triply periodic, statistically homogeneous cubic domains in the vicinity of the shear layer in the self-similar region. An a priori analysis is performed to calculate the effects of the different forcing terms and to predict the expected turbulence quantities. The forcing technique is then used to perform direct numerical simulations at different Reynolds numbers. Numerical results for the different cases are discussed and compared with results from experiments and other simulations of free shear turbulent flows. Anisotropy is observed both in the components of velocity and vorticity, with stronger Reynolds number dependence in the anisotropy of vorticity. Energy spectra obtained from the present homogeneous shear turbulence agree well with the spectra from temporally evolving shear layers. The results also highlight the effects of the additional forcing terms that were neglected in previous studies and the role of shear convection and the associated splitting errors in the unbounded evolution of previous numerical simulations.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1103/PhysRevFluids.4.084606DOIArticle
ORCID:
AuthorORCID
Rah, Kyupaeck Jeff0000-0003-1898-2930
Blanquart, Guillaume0000-0002-5074-9728
Additional Information:© 2019 American Physical Society. Received 20 December 2017; published 28 August 2019. We gratefully acknowledge financial support from the National Science Foundation. (CBET 1512771) and from the Air Force Office of Scientific Research (FA9550-16-1-0510) under the supervision of Dr. Chiping Li, and a graduate fellowship (C.D.) from the Resnick Sustainibility Institute at Caltech.
Group:Resnick Sustainability Institute
Funders:
Funding AgencyGrant Number
NSFCBET-1512771
Air Force Office of Scientific Research (AFOSR)FA9550-16-1-0510
Resnick Sustainability InstituteUNSPECIFIED
Issue or Number:8
Record Number:CaltechAUTHORS:20190828-092034904
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190828-092034904
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:98287
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:28 Aug 2019 16:25
Last Modified:03 Oct 2019 21:39

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