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k – l based hybrid LES/RANS approach and its application to heat transfer simulation
Author(s) -
Zhong Bowen,
Tucker Paul G.
Publication year - 2004
Publication title -
international journal for numerical methods in fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 112
eISSN - 1097-0363
pISSN - 0271-2091
DOI - 10.1002/fld.782
Subject(s) - reynolds averaged navier–stokes equations , turbulence , heat transfer , mechanics , computational fluid dynamics , computer science , mathematics , physics
Abstract To improve the compatibility of a k – l based hybrid LES/RANS approach, a controllable transitional zone is introduced to bridge the RANS and LES zones. This allows blending of the very different modelled turbulence length scales in these regions. To obtain a smooth variation of the length scales and transitional zone parameters different weighting functions are proposed. Results show the ‘RANS’ region has significant coherent unsteadiness. For Unsteady RANS (URANS) theoretical correctness, a favourable spectral gap between the modelled and resolved scales is required. The use of unsteadiness damping and time step filtering to ensure this is explored. Approaches are tested for a plane channel flow and the flow over a matrix of surface mounted cubes. The capability of the new hybrid LES/RANS method in improving heat transfer prediction in a conjugate heat transfer problem is examined. Numerical tests show that, compared to the RANS simulation, the proposed hybrid LES/RANS scheme performs well for the flow with large scale unsteadiness. It is also effective for improving the prediction of heat transfer. Copyright © 2004 John Wiley & Sons, Ltd.