DOI: 10.1615/ICHMT.2006.TurbulHeatMassTransf
ISBN Print: 978-1-56700-229-4
ISSN: 2377-2816
A New Irreducible Dynamic Nonlinear Tensor-Diffusivity SGS Heat-Flux Model for LES of Convective Flows
要約
In this paper, two new dynamic linear and nonlinear tensor diffusivity models are proposed for representing the subgrid-scale (SGS) heat flux (HF). The constitutive relation for the first model is based on Noll's formulation, which provides a nonlinear tensor diffusivity and is complete and irreducible. The first model represents a general formulation for SGS HF modelling based on the resolved strain rate tensor and temperature gradient vector. The constitutive relation for the second model is based on the linear subset of the Noll's formulation, which provides a general nonhomogeneous linear tensor diffusivity. Both proposed models are general in terms of the tensor polynomial expression and include the conventional dynamic eddy diffusivity model of Moin et al. [Phys. Fluids A, 3:2746-2757, 1991] and the dynamic homogeneous linear tensor diffusivity model of Peng and Davidson [Int. J. Heat Mass Trans., 45:1393-1405, 2002] as special cases. In contrast to the conventional SGS HF modelling approaches, the proposed models admit nonlinearity in tensor diffusivity, more degrees of freedom in tensor representation and non-alignment between the SGS HF and resolved temperature gradient, and therefore, allow for a more realistic geometrical representation of the SGS heat flux for large eddy simulation of thermal convection.