Title:
|
New subgrid-scale models for large-eddy simulation of Rayleigh-Bénard convection
|
Author:
|
Dabbagh, Firas; Trias Miquel, Francesc Xavier; Gorobets, Andrei; Oliva Llena, Asensio
|
Other authors:
|
Universitat Politècnica de Catalunya. Departament de Màquines i Motors Tèrmics; Universitat Politècnica de Catalunya. CTTC - Centre Tecnològic de la Transferència de Calor |
Abstract:
|
Published under licence in Journal of Physics: Conference Series by IOP Publishing Ltd.
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. |
Abstract:
|
At the crossroad between flow topology analysis and the theory of turbulence, a new eddy-viscosity model for Large-eddy simulation has been recently proposed by Trias et al.[PoF, 27, 065103 (2015)]. The S3PQR-model has the proper cubic near-wall behaviour and no intrinsic limitations for statistically inhomogeneous flows. In this work, the new model has been tested for an air turbulent Rayleigh-Benard convection in a rectangular cell of aspect ratio unity and n span-wise open-ended distance. To do so, direct numerical simulation has been carried out at two Rayleigh numbers Ra = 108 and 1010, to assess the model performance and investigate a priori the effect of the turbulent Prandtl number. Using an approximate formula based on the Taylor series expansion, the turbulent Prandtl number has been calculated and revealed a constant and Ra-independent value across the bulk region equals to 0.55. It is found that the turbulent components of eddy-viscosity and eddy-diffusivity are positively prevalent to maintain a turbulent wind essentially driven by the mean buoyant force at the sidewalls. On the other hand, the new eddy-viscosity model is preliminary tested for the case of Ra = 108 and showed overestimation of heat flux within the boundary layer but fairly good prediction of turbulent kinetics at this moderate turbulent flow. |
Abstract:
|
Peer Reviewed |
Subject(s):
|
-Àrees temàtiques de la UPC::Enginyeria mecànica::Mecànica de fluids -Rayleigh-Bénard convection -Simulation methods -Air -Boundary layer turbulence -Buoyancy -Confined flow -Flow simulation -Inhomogeneous media -Numerical analysis -Rayleigh-Bénard convection -Thermal diffusion -Viscosity -Subgrid-scale models -Large-Eddy simulation -S3PQR-model -Cubic near-wall behaviour -Statistically inhomogeneous flows -Air turbulent Rayleigh-Benard convection -Rectangular cell -Aspect ratio unity -Span-wise open-ended distance -Direct numerical simulation -Rayleigh numbers -Turbulent Prandtl number -Approximate formula based Taylor series expansion -Eddy-viscosity model -Eddy-diffusivity model -Mean buoyant force -Heat flux -Boundary layer -Rayleigh-Bénard, Convecció de -Simulació, Mètodes de |
Rights:
|
http://creativecommons.org/licenses/by/3.0/es/ |
Document type:
|
Article - Published version Conference Object |
Published by:
|
Institute of Physics (IOP)
|
Share:
|
|