Magnetohydrodynamic turbulence in a channel with spanwise magnetic field

Krasnov, Dmitry; Zikanov, Oleg; Schumacher, Jörg; Boeck, Thomas

doi:10.1063/1.2975988

Cited by 64 publications

(89 citation statements)

References 43 publications

(60 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This appears to be the reason for the reduced slope of the mean velocity profile in the cross-section Sh-Sh illustrated in figure 5. The same effect has been detected by Krasnov et al (2008) in a channel with spanwise magnetic field. For τ 13 , an interesting feature is that at its peak near the Hartmann wall, the transport rate is higher in the MHD flow at Ha = 100 than it is in the flow with Ha = 0.…”

Section: Turbulent Fluctuationssupporting

confidence: 62%

“…We see that when the Hartmann number increases from 0 to 100 and then to 200, the centreline velocity increases (see figures 4 and 5 and table 2). The distribution takes a form similar to the chisel-like form found earlier in the simulations of channel flow with a spanwise magnetic field (Krasnov et al 2008). This has been attributed to reduction of the wall-normal turbulent transport of momentum caused by the suppression of turbulence by the magnetic field.…”

Section: Mean Flowsupporting

confidence: 56%

“…The value of the smallest wall-normal grid step in the z A preliminary verification of the model was conducted by reproducing the results of Galletti & Bottaro (2004) for the transient growth in the hydrodynamic duct and the results of Boeck et al (2007) and Krasnov et al (2008) for turbulent MHD flows in channels. We have also conducted a grid sensitivity study.…”

Section: Physical Model and Numerical Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Numerical study of magnetohydrodynamic duct flow at high Reynolds and Hartmann numbers

2012

Self Cite

View full text Add to dashboard Cite

High-resolution direct numerical simulations are conducted to analyse turbulent states of the flow of an electrically conducting fluid in a duct of square cross-section with electrically insulating walls and imposed transverse magnetic field. The Reynolds number of the flow is 10 5 and the Hartmann number varies from 0 to 400. It is found that there is a broad range of Hartmann numbers in which the flow is neither laminar nor fully turbulent, but has laminar core, Hartmann boundary layers and turbulent zones near the walls parallel to the magnetic field. Analysis of turbulent fluctuations shows that each zone consists of two layers: the boundary layer near the wall characterized by small-scale turbulence and the outer layer dominated by large-scale vortical structures strongly elongated in the direction of the magnetic field. We also find a peculiar scaling of the mean velocity, according to which the reciprocal von Kármán coefficient grows nearly linearly with the distance to the wall.

show abstract

Section: Turbulent Fluctuationssupporting

confidence: 62%

Section: Mean Flowsupporting

confidence: 56%

Section: Physical Model and Numerical Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Numerical study of magnetohydrodynamic duct flow at high Reynolds and Hartmann numbers

2012

Self Cite

View full text Add to dashboard Cite

show abstract

“…Between the two limits, the flows have the transitional form discussed below. It is known from [18][19][20][21] and confirmed by our computations that the suppression of turbulence and reduction of momentum transport by the magnetic field result, in the considered range of Re and Ha, in a decrease of C f . After the flow becomes laminar, increase of Ha means thinner Hartmann and sidewall layers and, thus, stronger gradient of mean velocity near the walls and higher C f .…”

supporting

confidence: 71%

Patterned Turbulence in Liquid Metal Flow: Computational Reconstruction of the Hartmann Experiment

et al. 2013

Self Cite

View full text Add to dashboard Cite

“…The Lorentz force density in the fluid is f = j × B. The interaction between a laminar duct flow and a magnetic dipole is studied by direct numerical simulations with a highly conservative finite-difference method on a structured mesh [5]. Our code solves the incompressible Navier-Stokes equations together with the induction equation in the quasistatic approximation.…”

mentioning

confidence: 99%

Laminar magnetohydrodynamic duct flow in the presence of a magnetic dipole

Tympel

Krasnov

Boeck

et al. 2011

Proc Appl Math and Mech

Self Cite

View full text Add to dashboard Cite

We study magnetohydrodynamic flow of a liquid metal in a straight duct. The magnetic field is produced by an exterior magnetic dipole. This basic configuration is of fundamental interest for Lorentz force velocimetry (LFV), where the Lorentz force opposing the relative motion of conducting medium and magnetic field is measured to determine the flow velocity. The Lorentz force acts in equal strength but opposite direction on the flow as well as on the dipole. We are interested in the dependence of the velocity on the flow rate and on strength of the magnetic field as well as on geometric parameters such as distance and position of the dipole relative to the duct. To this end, we perform numerical simulations with an accurate finite-difference method in the limit of small magnetic Reynolds number, whereby the induced magnetic field is assumed to be small compared with the external applied field. The hydrodynamic Reynolds number is also assumed to be small so that the flow remains laminar. The simulations allow us to quantify the magnetic obstacle effect as a potential complication for local flow measurement with LFV. Lorentz force velocimetry (LFV) is a contactless method for velocity measurement in conducting bodies based on Lenz' rule of electromagnetic induction [1]. The braking force on the conductor moving through a stationary field of an external magnet system is accompanied by an opposite drag force of equal magnitude on the magnet system itself. This force depends on the magnitudes and spatial distributions of the velocity and magnetic induction. By measuring this force one can therefore determine the velocity of the conducting body. Potential applications of LFV include liquid metal flows in casting and other metallurgical processes, where direct contact between the sensor and the liquid metal should be avoided. The method can also be used for weakly conducting media such as hot glass melts or electrolytes.LFV offers not only the possibility to measure the mean flow velocity but also to determine local velocity information when the magnetic field is suitably localized. However, the Lorentz force will also modify the flow field. This mutual dependence of Lorentz force and flow field must be taken into account to obtain a profound understanding of LFV, which is also necessary for practical applications. From this perspective, LFV is also related to fundamental problems of magnetohydrodynamics such as the transformation of flow in ducts or channels under the influence of inhomogeneous magnetic fields. Currently, our interest in LFV is motivated by such fundamental aspects. For this reason, we focus on generic configurations for the flow and the magnetic field as a foundation for subsequent investigations of more realistic cases. Specifically, we choose a single dipole as the simplest model for a localized field, and a laminar inside a straight duct of square cross-section and infinite extent as conducting medium. We consider the geometry represented in Fig. 1. The dipole with magnetic moment m at distance h ...

show abstract

Magnetohydrodynamic turbulence in a channel with spanwise magnetic field

Cited by 64 publications

References 43 publications

Numerical study of magnetohydrodynamic duct flow at high Reynolds and Hartmann numbers

Numerical study of magnetohydrodynamic duct flow at high Reynolds and Hartmann numbers

Patterned Turbulence in Liquid Metal Flow: Computational Reconstruction of the Hartmann Experiment

Laminar magnetohydrodynamic duct flow in the presence of a magnetic dipole

Contact Info

Product

Resources

About