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Dynamic Evaluation of Mesh Resolution and Its Application in Hybrid LES/RANS Methods

Xiao, Heng ; Wang, Jianxun ; Jenny, Patrick

In: Flow, Turbulence and Combustion, 2014, vol. 93, no. 1, p. 141-170

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    Titre
    • Dynamic Evaluation of Mesh Resolution and Its Application in Hybrid LES/RANS Methods
    Auteur
    • Xiao, Heng. Department of Aerospace and Ocean Engineering, Virginia Tech, 24060, Blacksburg, VA, USA
    • Wang, Jianxun. Department of Aerospace and Ocean Engineering, Virginia Tech, 24060, Blacksburg, VA, USA
    • Jenny, Patrick. Institute of Fluid Dynamics, ETH Zürich, 8092, Zurich, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Flow, Turbulence and Combustion, 2014, vol. 93, no. 1, p. 141-170. Springer Netherlands
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:326175
    Summary
    In this work, we investigate a resolution evaluation criterion based on the ratio between turbulent length-scales and grid spacing within the context of dynamic resolution evaluation in hybrid LES/RANS simulations. A modified version of the commonly used length-scale criterion is adopted. The modified length-scale criterion is evaluated for a plane channel flow and compared to the criterion based on two-point correlations. Simulation results show qualitative agreement between the two criteria and physical predictions from both resolution indicators. These observations are confirmed by simulations of flows over periodic hills. It is further demonstrated that the length-scale based criterion is relatively less sensitive on variation of model parameters compared to criteria based on resolved percentage of turbulent quantities. The improved resolution criterion is applied in a dual-mesh hybrid LES/RANS solver. Numerical simulations with the hybrid solver suggest that the interactions between the length-scale resolution indicator and the solution are moderate, and that favorable comparisons with benchmark results are obtained. In summary, we demonstrate that the modified length-scale based resolution indicator performs satisfactorily in both pure LES and hybrid simulations. Therefore, it is selected as a promising candidate to provide reliable predictions of resolution adequacy for individual cells in hybrid LES/RANS simulations.