Numerical investigation of flow and heat transfer characteristics for attached and separated low-PR flows

S. Bhushan, M. Elmellouki, W. D. Jock, D. K. Walters, J. K. Lai, Y. A. Hassan, A. Obabko, E. Merzari

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This study performs a comprehensive analysis of the effect of flow separation and reattachment, convective conditions and Pr to understand their effect on heat transfer characteristics and the predictive capability of low- and hig- fidelity turbulence models are assessed. To achieve the objective DNS is performed for plane channel flow at Ret=640, Pr =0.71 and 0.025 involving mixed forced and natural convection condition, and RANS, hybrid RANS/LES, and LES calculations are performed for backward backing step with expansion ratio 1.5, Pr = 0.71 and 0.0088 and Ri = 0 and 0.338. Channel flow simulations reveal that the convective conditions affect the near-wall turbulent structures and thermal diffusion more significantly in high-Re flows that in low-Re flows. Thus, the generated DNS database provides a challenging test case for turbulence model validation. For backward facing step case, all the turbulence models predict the overall flow characteristics, and Ri = 0 case is a more challenging validation test case than Ri = 0.338, as the former involves complex turbulent diffusion, whereas the latter is dominated by large scale buoyancy driven convection. Results show that well resolved PANS and LES predictions can help in improve understanding of turbulent diffusion under complex convection and flow separation/ reattachment regimes. RANS results are also quite encouraging and indicates that they may represent a reasonable compromise between computational expense and accuracy for cases in which high resolution simulations are not feasible.

Original languageEnglish (US)
Title of host publicationComputational Fluid Dynamics
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791859032
DOIs
StatePublished - Jan 1 2019
EventASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019 - San Francisco, United States
Duration: Jul 28 2019Aug 1 2019

Publication series

NameASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019
Volume2

Conference

ConferenceASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019
CountryUnited States
CitySan Francisco
Period7/28/198/1/19

All Science Journal Classification (ASJC) codes

  • Fluid Flow and Transfer Processes

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    Bhushan, S., Elmellouki, M., Jock, W. D., Walters, D. K., Lai, J. K., Hassan, Y. A., Obabko, A., & Merzari, E. (2019). Numerical investigation of flow and heat transfer characteristics for attached and separated low-PR flows. In Computational Fluid Dynamics (ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019; Vol. 2). American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/AJKFluids2019-5273