Thermal convection in rotating spherical shells: An experimental and numerical approach within GeoFlow

Futterer, Birgit; Gellert, M.; Larcher, Thomas von; Egbers, Christoph

doi:10.1016/j.actaastro.2007.11.006

Cited by 15 publications

(6 citation statements)

References 9 publications

(9 reference statements)

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“…The corresponding electric gravity g e is also presented for the gap d = 5 mm. Considered liquids are the Baysilone R silicone oil M5 and the 1-Nonanol, which were used in the GeoFlow experiments [3,4] and should be used in future experiments with annular geometries in microgravity conditions. The imposed temperature difference ∆T is assumed to be 5 degrees.…”

Section: Discussionmentioning

confidence: 99%

“…With applying a radial temperature gradient and electric field, the dielectrophoretic force is aligned in the radial direction and can be deemed as an effective gravity that we call the electric gravity. Many geophysical problems can be simulated by this convection in the dielectric liquid [3,4]. The application of the temperature gradient and the electric field may be used for heat transfer enhancement in dielectric liquids and may yield large reductions in weight and volume of heat transfer systems.…”

Section: Introductionmentioning

confidence: 99%

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Thermo-electro-hydrodynamic instabilities in a dielectric liquid under microgravity

Malik¹,

Yoshikawa²,

Crumeyrolle³

et al. 2012

Acta Astronautica

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International audienceLinear stability analysis of a dielectric fluid confined in a cylindrical annulus of infinite length is performed under microgravity conditions. A radial temperature gradient and a high alternating electric field imposed over the gap induce an effective gravity that can lead to a thermal convection even in the absence of the terrestrial gravity. The linearized governing equations are discretized using a spectral collocation method on Chebyshev polynomials to compute marginal stability curves and the critical parameters of instability. The critical parameters are independent of the Prandtl number, but they depend on the curvature of the system. The critical modes are non-axisymmetric and are made of stationary helices

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermo-electro-hydrodynamic instabilities in a dielectric liquid under microgravity

Malik¹,

Yoshikawa²,

Crumeyrolle³

et al. 2012

Acta Astronautica

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“…Realization of laboratory experiments with an artificial radial gravity is a key to advance the understanding of these flows. Some attempts have been made with the thermoelectric artificial gravity in annular geometry [20,22,23] and in spherical geometry [24][25][26][27][28]. An experiment with the thermomagnetic artificial gravity has also been reported in annular geometry [29].…”

Section: Vkmentioning

confidence: 99%

Linear stability of a circular Couette flow under a radial thermoelectric body force

et al. 2015

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The stability of the circular Couette flow of a dielectric fluid is analyzed by a linear perturbation theory. The fluid is confined between two concentric cylindrical electrodes of infinite length with only the inner one rotating. A temperature difference and an alternating electric tension are applied to the electrodes to produce a radial dielectrophoretic body force that can induce convection in the fluid. We examine the effects of superposition of this thermoelectric force with the centrifugal force including its thermal variation. The Earth's gravity is neglected to focus on the situations of a vanishing Grashof number such as microgravity conditions. Depending on the electric field strength and of the temperature difference, critical modes are either axisymmetric or nonaxisymmetric, occurring in either stationary or oscillatory states. An energetic analysis is performed to determine the dominant destabilizing mechanism. When the inner cylinder is hotter than the outer one, the circular Couette flow is destabilized by the centrifugal force for weak and moderate electric fields. The critical mode is steady axisymmetric, except for weak fields within a certain range of the Prandtl number and of the radius ratio of the cylinders, where the mode is oscillatory and axisymmetric. The frequency of this oscillatory mode is correlated with a Brunt-Väisälä frequency due to the stratification of both the density and the electric permittivity of the fluid. Under strong electric fields, the destabilization by the dielectrophoretic force is dominant, leading to oscillatory nonaxisymmetric critical modes with a frequency scaled by the frequency of the inner-cylinder rotation. When the outer cylinder is hotter than the inner one, the instability is again driven by the centrifugal force. The critical mode is axisymmetric and either steady under weak electric fields or oscillatory under strong electric fields. The frequency of the oscillatory mode is also correlated with the Brunt-Väisälä frequency.

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“…A high-frequency electric field imposed on a dielectric fluid with a temperature gradient produces a dielectrophoretic (DEP) force (Landau & Lifshitz 1984), which can generate thermoelectric convective flows (Roberts 1969;Turnbull 1969;Chandra & Smylie 1972;Yoshikawa, Crumeyrolle & Mutabazi 2013;Travnikov, Crumeyrolle & Mutabazi 2015Mutabazi et al 2016). The existence of thermoelectric convective flows induced by DEP force has been evidenced in experiments performed in the microgravity environment of Spacelab 3 aboard the space shuttle Challenger (Hart, Glatzmaier & Toomre 1986), in the GeoFlow experiments performed on the International Space Station (Futterer et al 2008(Futterer et al , 2013 and in parabolic flight experiments (Dahley et al 2011;Meyer et al 2017Meyer et al , 2018Meyer et al , 2019Meier et al 2018). Besides the interest for microgravity environments, the existence of thermoelectric convection offers a new strategy of control of thermal convection in dielectric liquids and heat evacuation in systems using electric tension in plane or cylindrical heat exchangers, especially for microfluidic systems (Wadsworth & Mudawar 1990;McCluskey, Atten & Perez 1991;Barbic et al 2001;Lin 2009).…”

Section: Introductionmentioning

confidence: 99%

Columnar vortices induced by dielectrophoretic force in a stationary cylindrical annulus filled with a dielectric liquid

Kang

Mutabazi

2020

J. Fluid Mech.

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Thermal convection in rotating spherical shells: An experimental and numerical approach within GeoFlow

Cited by 15 publications

References 9 publications

Thermo-electro-hydrodynamic instabilities in a dielectric liquid under microgravity

Thermo-electro-hydrodynamic instabilities in a dielectric liquid under microgravity

Linear stability of a circular Couette flow under a radial thermoelectric body force

Columnar vortices induced by dielectrophoretic force in a stationary cylindrical annulus filled with a dielectric liquid

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