Title:
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Fine-scale dynamics in turbulent Rayleigh-Bénard convection
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Author:
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Dabbagh, Firas; Trias Miquel, Francesc Xavier; Gorobets, Andrei; Oliva Llena, Asensio
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Other authors:
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Universitat Politècnica de Catalunya. Departament de Màquines i Motors Tèrmics; Universitat Politècnica de Catalunya. CTTC - Centre Tecnològic de la Transferència de Calor |
Abstract:
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Small-scale universal features captured normally in many turbulent flows have been reviewed in Rayleigh-Bénard convection. Namely, dynamical Lagrangian representations of the velocity gradient tensor invariants have displayed the so-called “tearing drop” spiraling feature within the bulk region. Furthermore, essential common aspects as the asymmetric alignment of vorticity with the vortex-stretching vector, and the preferential alignment between vorticity and the intermediate eigenvector of the rate-of-strain tensor have been observed in that scope. Further and in more appropriate implement, we have performed a similar dynamical study of flow topology pertained to the traceless part of the gradient velocity-times-temperature tensor. The new invariants are related basically with the small-scale dynamics associated with the evolution of thermal plumes and buoyant production. We find that a self-amplification of velocity derivatives developed at harder turbulent flow supports indirectly the local effects of vortex-stretching generation. Moreover, the averaged evolution of the new invariants have revealed a converging change towards two skew-symmetric origins at Rayleigh number equals to 1e8 but one zero-valued origin at 1e10. |
Abstract:
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Peer Reviewed |
Subject(s):
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-Àrees temàtiques de la UPC::Enginyeria mecànica::Mecànica de fluids -Rayleigh-Bénard convection -Turbulence -Rayleigh-Bénard, Convecció de -Turbulència |
Rights:
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Document type:
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Article - Published version Conference Object |
Published by:
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Begell House
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