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arXiv · 2207.13060

A unified understanding of scale-resolving simulations and near-wall modeling of turbulent flows using optimal finite element projections

Aniruddhe Pradhan·Karthik Duraisamy
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Abstract

The main objective of this work is to develop a unified framework that can be used as a lens to quantitatively assess and augment a wide range of coarse-grained models of turbulence, viz. large eddy simulations (LES), hybrid Reynolds-averaged/LES methods and wall-modeled (WM)LES. Taking a turbulent channel flow as an example, optimality is assessed in the wall-resolved limit, the hybrid RANS/LES limit and the WMLES limit, via projections at different resolutions suitable for these approaches. These optimal a priori estimates are shown to have similar characteristics to existing a posteriori solutions reported in the literature. Consistent accuracy metrics are developed for scale-resolving methods using the optimal solution as a reference, and evaluations are performed. We further characterize the slip velocity in WMLES in terms of the near-wall under-resolution and develop a universal scaling relationship. Insights from the a-priori tests are used to augment existing slip-based wall models. Various a posteriori tests reveal superior performance over the dynamic slip wall model. Guidance for the development of improved slip-wall models is provided, including a target for the dynamic procedure.

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BibTeXRIS

Aniruddhe Pradhan, Karthik Duraisamy. 2022-07-26. A unified understanding of scale-resolving simulations and near-wall modeling of turbulent flows using optimal finite element projections. https://doi.org/10.1017/jfm.2022.1030

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