Results 11 to 20 of about 25,487 (265)
Prandtl and Rayleigh numbers dependences in Rayleigh-Bénard convection [PDF]
Europhysics Letters (EPL), 2002 Using low-temperature gaseous helium close to the critical point, we investigate the Prandtl-number dependence of the effective heat conductivity (Nusselt number) for a 1/2 aspect ratio Rayleigh-Benard cell. Very weak dependence is observed in the range 0.7 < Pr < 21; 2 × 108 < Ra < 2 × 1010: the absolute value of the average logarithmic slope δ = (∂ln
Roche, Philippe-Emmanuel +3 more
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Rayleigh and Prandtl number scaling in the bulk of Rayleigh–Bénard turbulence [PDF]
Physics of Fluids, 2005 The Ra and Pr number scaling of the Nusselt number Nu, the Reynolds number Re, the temperature fluctuations, and the kinetic and thermal dissipation rates is studied for (numerical) homogeneous Rayleigh–Bénard turbulence, i.e., Rayleigh–Bénard turbulence with periodic boundary conditions in all directions and a volume forcing of the temperature field ...
Calzavarini E. +3 more
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Critical Rayleigh number in Rayleigh-Bénard convection [PDF]
Quarterly of Applied Mathematics, 2009 Summary: The Rayleigh-Bénard convection is a classical problem in fluid dynamics. In the presence of rigid boundary condition, we identify the critical Rayleigh number \( R_{a}^{\ast }\) by a reduced variational problem. We prove nonlinear asymptotic stability for motionless steady states for \( R_{a}R_{a}^{\ast }.\) The dynamic of such instability is ...
Guo, Yan, Han, Yongqian
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Large-eddy simulation of Rayleigh–Bénard convection at extreme Rayleigh numbers
Physics of Fluids, 2022 We adopt the stretched spiral vortex sub-grid model for large-eddy simulation (LES) of turbulent convection at extreme Rayleigh numbers. We simulate Rayleigh–Bénard convection (RBC) for Rayleigh numbers ranging from 106 to 1015 and for Prandtl numbers 0.768 and 1. We choose a box of dimensions 1:1:10 to reduce computational cost. Our LES yields Nusselt
Roshan Samuel +2 more
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Rayleigh-Bénard convection at high Rayleigh number and infinite Prandtl number: Asymptotics and numerics [PDF]
Physics of Fluids, 2013 The problem of fast viscous steady Rayleigh-Bénard convection in a rectangular enclosure is revisited using asymptotic and numerical methods. There are two generic cases: in the first, there is zero shear stress at all boundaries; in the second, there is zero shear stress at the vertical boundaries, but no slip at the horizontal ones.
Vynnycky, Michael, Masuda, Y
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Prandtl and Rayleigh number dependence of heat transport in high Rayleigh number thermal convection [PDF]
Journal of Fluid Mechanics, 2011 AbstractResults from direct numerical simulation for three-dimensional Rayleigh–Bénard convection in samples of aspect ratio $\Gamma = 0. 23$ and $\Gamma = 1/ 2$ up to Rayleigh number $\mathit{Ra}= 2\ensuremath{\times} 1{0}^{12} $ are presented. The broad range of Prandtl numbers $0. 5\lt \mathit{Pr}\lt 10$ is considered.
Stevens, RJAM +2 more
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Optimal heat transport in rotating Rayleigh-Bénard convection at large Rayleigh numbers
Physical Review Fluids, 2023 Main article: 21 pages, 10 figures; Supplementary material: 6 pages, 4 figures; Published in Phys.
Hartmann, Robert +4 more
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A boundary-layer analysis of Rayleigh-Bénard convection at large Rayleigh number
Journal of Fluid Mechanics, 1987 A boundary-layer analysis is presented for the two-dimensional nonlinear convection of an infinite-Prandtl-number fluid in a rectangular enclosure, in the limit of large Rayleigh numbers. Particular emphasis is given to the analysis of the periodic boundary layers, and on the removal of the singularities that appear near the corners of the cell.
Jiménez Sendín, Javier +1 more
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Asymptotics of the number of Rayleigh resonances [PDF]
Mathematische Annalen, 1997 Resonances associated to the Neumann problem in linear elasticity are studied. It is well-known that for this problem there are surface waves called Rayleigh waves moving with a speed \(c_R>0\) strictly less than the two speeds in the exterior domain. For a class of obstacles including strictly convex ones the following asymptotic for the number, \(N(r)
Sjöstrand, Johannes, Vodev, Georgi
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High Rayleigh number variational multiscale large eddy simulations of Rayleigh-Bénard convection [PDF]
Mechanics Research Communications, 2021 The variational multiscale (VMS) formulation is used to develop residual-based VMS large eddy simulation (LES) models for Rayleigh-Bénard convection. The resulting model is a mixed model that incorporates the VMS model and an eddy viscosity model. The Wall-Adapting Local Eddy-viscosity (WALE) model is used as the eddy viscosity model in this work.
Sondak, David +4 more
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