A numerical study of flows driven by a rotating magnetic field in a square container

Fraňa, Karel; Stiller, Jörg; Horáková, K.

doi:10.1002/pamm.200810953

Cited by 4 publications

(6 citation statements)

References 5 publications

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“…The flow velocity exhibits four distinct maxima near the side walls of the cube and lower values at the corners. These results are in excellent agreement with the simulation [27,28]. The maximum velocity of the primary flow is 1.30 mm s −1 for Ta = 1 • 10 4 and 22.67 mm s −1 for Ta = 1 • 10 6 .…”

Section: Resultssupporting

confidence: 87%

“…Secondly, the positions of the four maxima move closer to the vessel walls as the Taylor number is increased. These circumstances were also predicted by simulations [27,28].…”

Section: Resultssupporting

confidence: 73%

“…In contrast, the flow in an ashlar-formed vessel with a square base is more complex since the corners in the horizontal cross-sections give rise to additional flow phenomena. Numeric simulations of this flow situation were published by Frana et al [27,28]. The aim of the experiments presented here is to characterize the flow structures in both the laminar as well as the turbulent flow regime and to prove numerically predicted flow structures.…”

Section: Flow Investigations In a Cubic Vessel Driven By A Rmfmentioning

confidence: 98%

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Dual-plane ultrasound flow measurements in liquid metals

Büttner¹,

Nauber²,

Bürger³

et al. 2013

Meas. Sci. Technol.

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An ultrasound measurement system for dual-plane, two-component flow velocity measurements especially in opaque liquids is presented. Present-day techniques for measuring local flow structures in opaque liquids disclose considerable drawbacks concerning line-wise measurement of single ultrasound probes. For studying time-varying flow patterns, conventional ultrasound techniques are either limited by time-consuming mechanical traversing or by the sequential operation of single probes. The measurement system presented within this paper employs four transducer arrays with a total of 100 single elements which allows for flow mapping without mechanical traversing. A high frame rate of several 10 Hz has been achieved due to an efficient parallelization scheme using time-division multiplexing realized by a microcontroller-based electronic switching matrix. The functionality and capability of the measurement system are demonstrated on a liquid metal flow at room temperature inside a cube driven by a rotating magnetic field (RMF). For the first time, the primary and the secondary flow have been studied in detail and simultaneously using a configuration with two crossed measurement planes. The experimental data confirm predictions made by numeric simulation. After a sudden switching on of the RMF, inertial oscillations of the secondary flow were observed by means of a time-resolved measurement with a frame rate of 3.4 Hz. The experiments demonstrate that the presented measurement system is able to investigate complex and transient flow structures in opaque liquids. Due to its ability to study the temporal evolution of local flow structures, the measurement system could provide considerable progress for fluid dynamics research, in particular for applications in the food industry or liquid metal technologies.

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Section: Resultssupporting

confidence: 87%

“…Secondly, the positions of the four maxima move closer to the vessel walls as the Taylor number is increased. These circumstances were also predicted by simulations [27,28].…”

Section: Resultssupporting

confidence: 73%

Section: Flow Investigations In a Cubic Vessel Driven By A Rmfmentioning

confidence: 98%

See 1 more Smart Citation

Dual-plane ultrasound flow measurements in liquid metals

Büttner¹,

Nauber²,

Bürger³

et al. 2013

Meas. Sci. Technol.

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show abstract

“…Furthermore, non‐equilibrium fluctuations in micro‐MHD effects derived from the Lorentz force acting on moving charged particles have recently been discussed [Aogaki et al, 2010]. In addition, studies of the MHD flow turbulence induced by RMF in liquid metals (e.g., mercury, which is a diamagnetic and conductive material) and melting crystals (e.g., bismuth silicon oxide, which is a diamagnetic and conductive material) under rapid RMF exposure (e.g., field strength 25 mT, frequency 50 Hz) have been conducted using a numerical calculation that employs a combination of the Navier–Stokes equations of fluid dynamics and Maxwell's equations of electromagnetism [Barz et al, 1997; Gelfgat et al, 2000; Rädler et al, 2003; Lorrain et al, 2006; Fraňa et al, 2008; Rädler and Brandenburg, 2010]. In principle, rapid RMFs generate eddy currents or ion motions in electric conductive melt and induce the Lorentz force, which occurs at right angles to both the current and the MF [Sakai et al, 2010].…”

Section: Discussionmentioning

confidence: 99%

Modulation of the shape and speed of a chemical wave in an unstirred Belousov–Zhabotinsky reaction by a rotating magnet

Okano

Kitahata

2012

Bioelectromagnetics

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The objective of this study was to observe whether a rotating magnetic field (RMF) could change the anomalous chemical wave propagation induced by a moderate-intensity gradient static magnetic field (SMF) in an unstirred Belousov-Zhabotinsky (BZ) reaction. The application of the SMF (maximum magnetic flux density = 0.22 T, maximum magnetic flux density gradient = 25.5 T/m, and peak magnetic force product (flux density × gradient) = 4 T(2) /m) accelerated the propagation velocity in a two-dimensional pattern. Characteristic anomalous patterns of the wavefront shape were generated and the patterns were dependent on the SMF distribution. The deformation and increase in the propagation velocity were diminished by the application of an RMF at a rotation rate of 1 rpm for a few minutes. Numerical simulation by means of the time-averaged value of the magnetic flux density gradient or the MF gradient force over one rotation partially supported the experimental observations. These considerations suggest that RMF exposure modulates the chemical wave propagation and that the degree of modulation could be, at least in part, dependent on the time-averaged MF distribution over one rotation. Bioelectromagnetics 34:220-230, 2013. © 2012 Wiley Periodicals, Inc.

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“…Experimental setup: GaInSn in a plexiglas cube driven by a rotating magnetic field stirrer4. Measurement resultsIn a first experiment a stationary rotating magnetic field with a field strength of B 0 = 4.8 mT at an angular frequency ω RMF = 2π•50 Hz was applied indicating a fully developed turbulent flow in the experiment[9].…”

mentioning

confidence: 99%