Influence of the spatial resolution on fine-scale features in DNS of turbulence generated by a single square grid |
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Authors: | Sylvain Laizet Jovan Nedić Christos Vassilicos |
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Affiliation: | Department of Aeronautics, Turbulence, Mixing and Flow Control Group, Imperial College London, South Kensington Campus, London, UK |
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Abstract: | We focus in this paper on the effect of the resolution of direct numerical simulations (DNS) on the spatio-temporal development of the turbulence downstream of a single square grid. The aims of this study are to validate our numerical approach by comparing experimental and numerical one-point statistics downstream of a single square grid and then investigate how the resolution is impacting the dynamics of the flow. In particular, using the Q–R diagram, we focus on the interaction between the strain-rate and rotation tensors, the symmetric and skew-symmetric parts of the velocity gradient tensor, respectively. We first show good agreement between our simulations and hot-wire experiment for one-point statistics on the centreline of the single square grid. Then, by analysing the shape of the Q–R diagram for various streamwise locations, we evaluate the ability of under-resolved DNS to capture the main features of the turbulence downstream of the single square grid. |
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Keywords: | direct numerical simulation turbulence |
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