Publication Date:
2019-06-20
Description:
The wake structure of an incompressible, conducting, viscous fluid past an electrically insulating sphere affected by a transverse magnetic field is investigated numerically over flow regimes including steady and unsteady laminar flows at Reynolds numbers up to 300. For a steady axisymmetric flow affected by a transverse magnetic field, the wake structure is deemed to be a double plane symmetric state. For a periodic flow, unsteady vortex shedding is first suppressed and transitions to a steady plane symmetric state and then to a double plane symmetric pattern. Wake structures in the range 〈![CDATA[$210 without a magnetic field have a symmetry plane. An angle exists between the orientation of this symmetry plane and the imposed transverse magnetic field. For a given transverse magnetic field, the final wake structure is found to be independent of the initial flow configuration with a different angle . However, the orientation of the symmetry plane tends to be perpendicular to the magnetic field, which implies that the transverse magnetic field can control the orientation of the wake structure of a free-moving sphere and change the direction of its horizontal motion by a field-wake-trajectory control mechanism. An interesting 'reversion phenomenon' is found, where the wake structure of the sphere at a higher Reynolds number and a certain magnetic interaction parameter corresponds to a lower Reynolds number with a lower value. Furthermore, the drag coefficient is proportional to for weak magnetic fields or to for strong magnetic fields, where the threshold value between these two regimes is approximately . © 2019 Cambridge University Press.
Print ISSN:
0022-1120
Electronic ISSN:
1469-7645
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Permalink