Convective stability of fluid in a rotating horizontal annulus

“…In such a statement, the equations obtained by the averaging method [4] describe the steady convection that corresponds to the thermovibrational one. The experimental and theoretical studies of steady convection in rotating around the horizontal axis cavities [5][6][7] prove the efficiency of this convection excitation mechanism and the correctness of the theoretical model.…”

Section: Introductionmentioning

confidence: 67%

“…Earlier in [6,7] the excitation threshold of thermal convection in a thin cylindrical layer of liquid rotating around the horizontal axis of symmetry was studied. It was shown that, regardless of the direction of heating in the layer, the excitation of "vibrational" thermal convection is possible, despite the absence of the cavity oscillations.…”

Section: Resultsmentioning

confidence: 99%

“…Let us consider the thermal vibrational convection of a liquid layer formed by two horizontal coaxial cylindrical surfaces having different temperatures and rotating around the symmetry axis with the same angular velocity. This problem has been systematically studied in thin layers experimentally and theoreticall+y [6,7]. The latter includes a linear stability analysis and a numerical study of stationary convection and heat transfer in the supercritical region of parameters.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermal “Vibrational” Convection in Thick Rotating Horizontal Annulus

Vjatkin¹,

Sabirov²,

Козлов³

2023

Proceedings of the 10th International Conference on Fluid Flow, Heat and Mass Transfer (FFHMT 2023)

View full text Add to dashboard Cite

This paper presents the results of an experimental study of thermal convection in a thick rotating horizontal annulus. The boundaries of the annulus have different temperatures; the inner one is hotter. Thus, the centrifugal mechanism of thermal convection plays a stabilizing role. It is found that with a decrease in the rotation rate, a non-isothermal liquid loses its stability. Two-dimensional rolls, elongated along the axis of rotation, appear in a threshold manner. These rolls are steady in the frame of the rotating cavity and belong to the thermal "vibrational" convection -the averaged convection excited by an oscillating force field. In the case under consideration, the gravitational field is responsible for the excitation of the vibrational convection; it rotates in the cavity framework and excites oscillations of the non-isothermal fluid. This conclusion is supported by the good agreement between the threshold of steady convection excitation and the results of linear stability theory, as well as by the similarity with thermovibrational convection in a thin layer, which was previously studied experimentally and theoretically. In parallel with two-dimensional steady convective rolls, fluid oscillations result in the excitation of inertial waves. The latter excites steady toroidal vortices of relatively low intensity in the annulus. A new phenomenon that we find in thick annulus experiments is two-dimensional oscillatory convective patterns that appear below the threshold of steady thermovibrational convection excitation. It is found that in the cavity frame, these rolls oscillate with a frequency that is two times less than the rotation rate. Both convective regimes, steady and oscillatory, lead to a significant increase in heat transfer.

show abstract

“…Thermal convection and heat transfer in a rotating horizontal annulus, with different constant temperatures set at the boundaries [1], are investigated theoretically and experimentally. Consideration is carried out from the standpoint of thermal vibrational convectionconvection caused by the average lift force generated as a result of oscillations of nonisothermal fluid with respect to the cavity.…”

Section: Extended Abstractmentioning

confidence: 99%