期刊
JOURNAL OF FLUID MECHANICS
卷 858, 期 -, 页码 122-144出版社
CAMBRIDGE UNIV PRESS
DOI: 10.1017/jfm.2018.770
关键词
computational methods; quasi-geostrophic flows; turbulence modelling
资金
- US Department of Energy, Office of Science, Office of Advanced Scientific Computing Research [DE-SC0019290]
- NVIDIA Corporation
- Oklahoma NASA EPSCoR Research Initiation Grant programme
- Norwegian Research Council
- OPWIND: Operational Control for Wind Power Plants [268044/E20]
- agency of the United States Government
In this investigation, a data-driven turbulence closure framework is introduced and deployed for the subgrid modelling of Kraichnan turbulence. The novelty of the proposed method lies in the fact that snapshots from high-fidelity numerical data are used to inform artificial neural networks for predicting the turbulence source term through localized grid-resolved information. In particular, our proposed methodology successfully establishes a map between inputs given by stencils of the vorticity and the streamfunction along with information from two well-known eddy-viscosity kernels. Through this we predict the subgrid vorticity forcing in a temporally and spatially dynamic fashion. Our study is both a priori and a posteriori in nature. In the former, we present an extensive hyper-parameter optimization analysis in addition to learning quantification through probability-density-function-based validation of subgrid predictions. In the latter, we analyse the performance of our framework for flow evolution in a classical decaying two-dimensional turbulence test case in the presence of errors related to temporal and spatial discretization. Statistical assessments in the form of angle-averaged kinetic energy spectra demonstrate the promise of the proposed methodology for subgrid quantity inference. In addition, it is also observed that some measure of a posteriori error must be considered during optimal model selection for greater accuracy. The results in this article thus represent a promising development in the formalization of a framework for generation of heuristic-free turbulence closures from data.
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