The effect of the cell tilting on the temperature oscillation in turbulent Rayleigh-Bénard convection

Chen，Xin1,2; Xu，Ao2; Xia，Ke Qing3; Xi，Heng Dong2

2023-08-01

10.1063/5.0165069

Physics of Fluids   Impact Factor & Quartile

1070-6631

1089-7666

We experimentally studied the effect of cell tilting on the temperature oscillation in turbulent Rayleigh-Bénard convection. We simultaneously measured the temperature using both in-fluid and in-wall thermistors for R a = 1.7 × 10 9 and 5.0 × 10 9 at Prandtl number Pr = 5.3. The tilt angles relative to gravity are set to 0 ° , 0.5 ° , 1 ° , 2 ° , and 7 ° . It is found that the temperature oscillation intensity measured in-fluid is much stronger than that measured in-wall, because the in-fluid thermistors measure both the large-scale circulation (LSC) and the plumes/plume clusters, while the in-wall thermistors only measure the LSC due to the filter effect of the sidewall. Despite the intensity difference, the obtained azimuthal profiles of the oscillation intensity measured by in-fluid and in-wall share similar spatial distribution, and the spatial distribution can be explained by the torsional motion near the top and bottom plates and the sloshing motion at the mid-height. With the in-fluid measurements, we find that with the increase in the tilt angle, the azimuthal profile of oscillation evolves toward a sawtooth-like profile and the intensity gets more prominent, which implies that the temperature oscillation becomes more coherent. Through a conditional sampling method based on the azimuthal position of LSC, we reveal that the uniformly distributed oscillation intensity in the level cell is the result of the superimposition of the random azimuthal motion and the sloshing motion. Tilting the cell can efficiently disentangle the above-mentioned two types of motions of LSC. Moreover, we found that the frequency of the temperature oscillation increases when the tilt angle increases, while the amplitude of the sloshing motion of the LSC remains unchanged, which is believed to be related to the confinement of the convection cell.

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English

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This work was supported by the National Natural Science Foundation of China (NSFC) under Grant No. 12125204, the China Postdoctoral Science Foundation under Grant No. 2021M702077, and the 111 Project of China (No. B17037). The experiment was conducted at t[2021M702077] ; National Natural Science Foundation of China (NSFC)[B17037] ; null[12125204]

Mechanics ; Physics

Mechanics ; Physics, Fluids & Plasmas

WOS:001057047000002

AIP Publishing

PHYSICS

2-s2.0-85169976831

Scopus

1.Shanghai Key Laboratory of Mechanics in Energy Engineering,Shanghai Institute of Applied Mathematics and Mechanics,School of Mechanics and Engineering Science,Shanghai University,Shanghai,200072,China
2.School of Aeronautics,Institute of Extreme Mechanics,Northwestern Polytechnical University,Xi'an,710072,China
3.Center for Complex Flows and Soft Matter Research,Department of Mechanics and Aerospace Engineering,Southern University of Science and Technology,Shenzhen,518055,China

Chen，Xin,Xu，Ao,Xia，Ke Qing,et al. The effect of the cell tilting on the temperature oscillation in turbulent Rayleigh-Bénard convection[J]. Physics of Fluids,2023,35(8).

Chen，Xin,Xu，Ao,Xia，Ke Qing,&Xi，Heng Dong.(2023).The effect of the cell tilting on the temperature oscillation in turbulent Rayleigh-Bénard convection.Physics of Fluids,35(8).

Chen，Xin,et al."The effect of the cell tilting on the temperature oscillation in turbulent Rayleigh-Bénard convection".Physics of Fluids 35.8(2023).