Connecting flow structures and heat flux in turbulent Rayleigh-Bénard convection

Abstract

The aspect ratio (Γ) dependence of the heat transfer (Nusselt number Nu in dimensionless form) in turbulent (two-dimensional) Rayleigh-Bénard convection is numerically studied in the regime $0.4\le \Gamma \le 1.25$ for Rayleigh numbers $10^7\le Ra\le R{a}^9$ and Prandtl numbers Pr =0.7 (gas) and 4.3 (water). Nu (Γ) shows a very rich structure with sudden jumps and sharp transitions. We connect these structures to the way the flow organizes itself in the sample and explain why the aspect ratio dependence of Nu is more pronounced for small Pr. Even for fixed Γdifferent turbulent states (with different resulting Nu) can exist, between which the flow can or cannot switch. In the latter case the heat transfer thus depends on the initial conditions.

4 pages, 6 figures

References in corpus (11)

• Flow reversals in thermally driven turbulence
• A Comparison of Turbulent Thermal Convection Between Conditions of Constant Temperature and Constant Flux
• Aspect ratio dependence of heat transfer and large-scale flow in turbulent convection
• On the triggering of the Ultimate Regime of convection
• Slow dynamics in a turbulent von Kármán swirling flow
• Dynamo regimes and transitions in the VKS experiment
• Finite-size effects lead to supercritical bifurcations in turbulent rotating Rayleigh-Bénard convection
• Bi-stability in turbulent, rotating spherical Couette flow
• On the properties of steady states in turbulent axisymmetric flows
• Non-Oberbeck-Boussinesq effects in two-dimensional Rayleigh-Benard convection in glycerol
• Non-Oberbeck-Boussinesq effects in turbulent thermal convection in ethane close to the critical point

Cited by in corpus (29)

• Comparison between two and three dimensional Rayleigh-Bénard convection
• Multiple states in highly turbulent Taylor-Couette flow
• Turbulent thermal superstructures in Rayleigh-Bénard convection
• Flow states in two-dimensional Rayleigh-Bénard convection as a function of aspect-ratio and Rayleigh number
• Multiple states in turbulent large-aspect ratio thermal convection: What determines the number of convection rolls?
• Elliptical Instability and Multi-Roll Flow Modes of the Large-scale Circulation in Confined Turbulent Rayleigh-Bénard Convection
• Aspect ratio dependence of heat transport by turbulent Rayleigh-Bénard convection in rectangular cells
• Correlation of internal flow structure with heat transfer efficiency in turbulent Rayleigh-Bénard convection
• Convective outgassing efficiency in planetary magma oceans: insights from computational fluid dynamics
• Counter-gradient heat transport in two-dimensional turbulent Rayleigh-Bénard convection
• Effect of tilting on turbulent convection: Cylindrical samples with aspect ratio $\Gamma =0.50$
• Tristable flow states and reversal of the large-scale circulation in two-dimensional circular convection cells
• Wall-sheared thermal convection: heat transfer enhancement and turbulence relaminarization
• Flow reversals in turbulent convection with free-slip walls
• Collapse of Coherent Large Scale Flow in Strongly Turbulent Liquid Metal Convection
• Sidewall effects in Rayleigh-Bénard convection
• Effect of aspect-ratio on vortex distribution and heat transfer in rotating Rayleigh-Bénard convection
• Large-eddy simulation of Rayleigh-Bénard convection at extreme Rayleigh numbers
• Heat transfer enhancement in Rayleigh-Bénard convection using a single passive barrier
• Coherent Solutions and Transition to Turbulence in Two-Dimensional Rayleigh-Bénard Convection
• Double maxima of angular momentum transport in $\eta =0.91$ TC turbulence
• Production and transport of vorticity in two-dimensional Rayleigh-Bénard convection cell
• Turbulent Rayleigh-Bénard convection described by projected dynamics in phase space
• Transient and steady convection in two dimensions
• Collective variables between large-scale states in turbulent convection
• Non-universal transport mechanisms in vertical natural convection with dispersed light droplets
• Effects of radius ratio on annular centrifugal Rayleigh-Bénard convection
• Bifurcation and multiple states in plane Couette flow with spanwise rotation
• Universal properties of penetrative turbulent Rayleigh--Bénard convection in cold water near $4^{\circ }\mathrm{C}$