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A NEW DYNAMIC GGDH SUBGRID-SCALE HEAT FLUX MODEL FOR LARGE-EDDY SIMULATION OF TURBULENT THERMAL FLOWS

Bing-Chen Wang
Department of Mechanical & Manufacturing Engineering, University of Manitoba, Winnipeg, MB, R3T 5V6, Canada

Eugene Yee
Defence Research & Development Canada − Suffield P.O. Box 4000, Medicine Hat, Alberta, T1A 8K6, Canada

Donald J. Bergstrom
Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, S7N 5A9, Canada

Jing Yin
Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, S7N5A9, Canada

Abstract

In this research, two new dynamic tensor diffusivity subgrid-scale (SGS) heat flux (HF) models are proposed for large-eddy simulation (LES) of thermal convection. The linear and nonlinear constitutive relations for these two new modelling approaches represent the most general explicit algebraic formulations possible for the family of SGS HF models constructed using the resolved temperature gradient and SGS stress tensor. As a result, these two proposed models include a number of previous dynamic SGS HF models as special cases. In contrast to the conventional dynamic eddy thermal diffusivity SGS HF model, both proposed models admit more degrees of freedom, allow non-alignment between the SGS heat flux and negative resolved temperature gradient vectors, and therefore, provide a more realistic geometrical and physical representation for the SGS heat flux vector. To validate the proposed models, numerical simulations have been performed based on a benchmark test case of an unstably stratified horizontal channel flow.