The influence of the cell inclination on the heat transport and large-scale circulation in liquid metal convection

Zwirner, Lukas; Khalilov, R.; Kolesnichenko, I.; Mamykin, A. D.; Mandrykin, Sergei; Pavlinov, A.; Шестаков, А. В.; Teimurazov, Andrei; Frick, Peter; Shishkina, Olga

doi:10.1017/jfm.2019.935

Cited by 36 publications

(43 citation statements)

References 99 publications

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“…Geometrical confinement provides an additional way to enhance heat transfer via plume condensation (14,15), despite an intermediate range of the cell aspect ratio only. Very recently, the combination of inclination of the convection cell and confined geometries was found to be able to lead to an increase of heat transport for several times, especially for low Prandtl numbers and relatively low Rayleigh numbers (16,17). Up to now, how to severely improve the efficiency of the global heat transport through the RB convection is still highly desirable, which is the main goal of the present investigation.…”

Section: Introductionmentioning

confidence: 88%

Vibration-induced boundary-layer destabilization achieves massive heat-transport enhancement

2020

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Thermal turbulence is well known as a potent means to convey heat across space by a moving fluid. The existence of the boundary layers near the plates, however, bottlenecks its heat-exchange capability. Here, we conceptualize a mechanism of thermal vibrational turbulence that breaks through the boundary-layer limitation and achieves massive heat-transport enhancement. When horizontal vibration is applied to the convection cell, a strong shear is induced to the body of fluid near the conducting plates, which destabilizes thermal boundary layers, vigorously triggers the eruptions of thermal plumes, and leads to a heat-transport enhancement by up to 600%. We further reveal that such a vibration-induced shear can very efficiently disrupt the boundary layers. The present findings open a new avenue for research into heat transport and will also bring profound changes in many industrial applications where thermal flux through a fluid is involved and the mechanical vibration is usually inevitable.

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Section: Introductionmentioning

confidence: 88%

Vibration-induced boundary-layer destabilization achieves massive heat-transport enhancement

2020

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“…2016; Zwirner et al. 2020), which are clearly absent in 2-D RBC. Therefore, the observed similarity between the – scaling in our low- convection and that in 3-D RBC requires a more detailed investigation, which is beyond the scope of the present work.…”

Section: Global Transports and Flow Structurementioning

confidence: 98%

“…2018 a ; Zwirner et al. 2020). Due to inadequate spatial resolution, the velocity and temperature derivatives, and, in turn, the viscous and thermal dissipation rates, are inaccurately estimated.…”

Section: Details Of Direct Numerical Simulationsmentioning

confidence: 99%

Thermal boundary layer structure in low-Prandtl-number turbulent convection

Pandey¹

2021

J. Fluid Mech.

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“…In particular, we calculate the transition between the different regimes in phase space and show how they depend on the Rayleigh and Prandtl numbers, which represent the ratios between buoyancy and viscosity and between momentum diffusivity and thermal diffusivity, respectively. Our modulation method is complementary to hitherto used concepts of using additional body force or modifying the spatial structure of the system to enhance heat transport, for example, adding surface roughness [30][31][32], shaking the convection cell [33], including additional stabilizing forces through geometrical modification [34][35][36], rotation [37], inclination [38,39], or a second stabilizing scalar field [40].…”

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confidence: 99%

Periodically Modulated Thermal Convection

et al. 2020

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Many natural and industrial turbulent flows are subjected to time-dependent boundary conditions. Despite being ubiquitous, the influence of temporal modulations (with frequency f) on global transport properties has hardly been studied. Here, we perform numerical simulations of Rayleigh-Bénard convection with time periodic modulation in the temperature boundary condition and report how this modulation can lead to a significant heat flux (Nusselt number Nu) enhancement. Using the concept of Stokes thermal boundary layer, we can explain the onset frequency of the Nu enhancement and the optimal frequency at which Nu is maximal, and how they depend on the Rayleigh number Ra and Prandtl number Pr. From this, we construct a phase diagram in the 3D parameter space (f, Ra, Pr) and identify the following: (i) a regime where the modulation is too fast to affect Nu; (ii) a moderate modulation regime, where Nu increases with decreasing f, and (iii) slow modulation regime, where Nu decreases with further decreasing f. Our findings provide a framework to study other types of turbulent flows with timedependent forcing.

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The influence of the cell inclination on the heat transport and large-scale circulation in liquid metal convection

Cited by 36 publications

References 99 publications

Vibration-induced boundary-layer destabilization achieves massive heat-transport enhancement

Vibration-induced boundary-layer destabilization achieves massive heat-transport enhancement

Thermal boundary layer structure in low-Prandtl-number turbulent convection

Periodically Modulated Thermal Convection

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