Energy spectra and turbulence generation in the wake of magnetic obstacles

Kenjereš, Saša

doi:10.1063/1.4767726

Cited by 19 publications

(5 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, they describe a decrease of the Strouhal number for increasing Hartmann number with values around St ∼ 0.1. In a similar parameter study, Kenjeres (2012)29 finds for the same interaction parameters as in our study St = 0.282 which is calculated from power spectra at several positions close to the magnetic obstacle. In the present work, the width of the area of reversed flow is used as a characteristic length of the magnetic obstacle.…”

supporting

confidence: 81%

“…12 have termed it magnetic obstacle in analogy with the flow around a solid obstacle. Similar configurations have been investigated both experimentally and numerically 6,7,29,59,60 . The magnetic fields in these works typically had a lower degree of spatial non-uniformity, and cannot be characterized in such as simple way as a point dipole.…”

Section: Introductionmentioning

confidence: 82%

See 1 more Smart Citation

Laminar and transitional liquid metal duct flow near a magnetic point dipole

2013

View full text Add to dashboard Cite

The flow transformation and the generation of vortex structures by a strong magnetic dipole field in a liquid metal duct flow is studied by means of three-dimensional direct numerical simulations. The dipole is considered as the paradigm for a magnetic obstacle which will deviate the streamlines due to Lorentz forces acting on the fluid elements. The duct is of square cross-section. The dipole is located above the top wall and is centred in spanwise direction. Our model uses the quasistatic approximation which is applicable in the limit of small magnetic Reynolds numbers. The analysis covers the stationary flow regime at small hydrodynamic Reynolds numbers Re as well as the transitional time-dependent regime at higher values which may generate a turbulent flow in the wake of the magnetic obstacle. We present a systematic study of these two basic flow regimes and their dependence on Re and on the Hartmann number Ha, a measure of the strength of the magnetic dipole field. Furthermore, three orientations of the dipole are compared: streamwise-, spanwise-and wall-normaloriented dipole axes. The most efficient generation of turbulence at a fixed distance above the duct follows for the spanwise orientation, which is caused by a certain configuration of Hartmann layers and reversed flow at the top plate. The enstrophy in the turbulent wake grows linearly with Ha which is connected with a dominance of the wall-normal derivative of the streamwise velocity.

show abstract

supporting

confidence: 81%

Section: Introductionmentioning

confidence: 82%

Laminar and transitional liquid metal duct flow near a magnetic point dipole

2013

View full text Add to dashboard Cite

show abstract

“…10 The obstruction may also take a non-solid form, such as fringing magnetic fields. [11][12][13][14] When a conducting fluid passes the localized zone of applied magnetic field, referred to as a magnetic obstacle, shear layers around the obstacle develop into time periodic vortical structures. Previous research has also shown that inhomogeneous wall conductivity may generate unstable internal shear layers and leads to a time-dependent flow similar to the wake produced behind bluff bodies.…”

Section: Introductionmentioning

confidence: 99%

Spatial evolution of a quasi-two-dimensional Kármán vortex street subjected to a strong uniform magnetic field

2015

View full text Add to dashboard Cite

Spatial evolution of a quasi-two-dimensional Kármán vortex street subjected to a strong uniform magnetic field A vortex decay model for predicting spatial evolution of peak vorticity in a wake behind a cylinder is presented. For wake vortices in the stable region behind the formation region, results have shown that the presented model has a good capability of predicting spatial evolution of peak vorticity within an advecting vortex across 0.1 ≤ β ≤ 0.4, 500 ≤ H ≤ 5000, and 1500 ≤ Re L ≤ 8250. The model is also generalized to predict the decay behaviour of wake vortices in a class of quasi-two-dimensional magnetohydrodynamic duct flows. Comparison with published data demonstrates remarkable consistency. C 2015 AIP Publishing LLC.

show abstract

“…Here, the imprints of the patterned turbulence structures are particularly visible in the form of quasi-periodic signals for the C d ¼ 0:1 case. Corresponding power spectra density (PSD) distributions 47 are shown in Fig. 15.…”

Section: (E)-3(h)mentioning

confidence: 99%

Turbulence suppression and regeneration in a magnetohydrodynamic duct flow due to influence of arbitrary electrically conductive walls

Blishchik

Kenjereš

2022

Physics of Fluids

Self Cite

View full text Add to dashboard Cite

In the current study, we present a series of numerical simulations describing a turbulent magnetohydrodynamic flow subjected to a transverse magnetic field in a square duct with arbitrary electrically conductive walls. The characteristic flow and electromagnetic non-dimensional parameters (Reynolds and Hartmann number, respectively) were fixed, while the wall conductivity ratio ( Cd) was varied from the perfectly electrically insulated ( Cd = 0) to perfectly electrically conducting ([Formula: see text]). We have assumed the one-way coupling between the flow of an electrically conducting fluid and the imposed magnetic field. The influence of the electrically conducting walls was imposed by simulating additional finite solid domains coupled with the channel interior. The turbulence was simulated by applying the large eddy simulation approach with the dynamic Smagorinsky sub-grid scale model. The obtained results confirmed a significant impact of the conductivity of the surrounding walls on the flow and turbulence reorganization. We have observed that the initially fully developed turbulence regime was gradually suppressed in the [Formula: see text] range, while the fully laminarized state was obtained at [Formula: see text]. We found that the process of turbulence suppression was accompanied by the appearance of the patterned turbulence phenomenon in the proximity of the walls parallel to the magnetic field direction. With a further increase in the wall conductivity parameter ([Formula: see text]), we have observed a complete turbulence regeneration. We found that this turbulence regeneration was caused by the local reorganization of the total current density loops near the electrically conducting walls.

show abstract

Energy spectra and turbulence generation in the wake of magnetic obstacles

Cited by 19 publications

References 43 publications

Laminar and transitional liquid metal duct flow near a magnetic point dipole

Laminar and transitional liquid metal duct flow near a magnetic point dipole

Spatial evolution of a quasi-two-dimensional Kármán vortex street subjected to a strong uniform magnetic field

Turbulence suppression and regeneration in a magnetohydrodynamic duct flow due to influence of arbitrary electrically conductive walls

Contact Info

Product

Resources

About