Critical strength of an electric field whereby a bubble can adopt a steady shape

Shaw, Stephen J.; Spelt, Peter D. M.

doi:10.1098/rspa.2009.0162

Cited by 8 publications

(4 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Specifically, we expand the shape functionr in terms of the spherical harmonics Y m (θ , φ), wherẽ r ≡ r/R, θ and φ are the dimensionless radial distance, polar angle and azimuthal angle, with respect to the centre of the drop. Such expansions have been employed in 10 -1 10 -2 10 1 5 50 0 0.2 0.4 0.6 0.8 1.0 0 0.2 0.4 0.6 0.8 1.0 10 0 10 -1 10 -2 10 2 10 1 10 0 10 -1 10 3 10 2 10 1 (a) ( b) previous works to study the dynamics of drops under sudden increase or decrease, as well as oscillations, of electric fields (Basaran et al 1995), the motion of bubbles in inviscid fluids (Meiron 1989;Kushch et al 2002) and the stability of bubbles under electric fields (Shaw & Spelt 2009). Owing to the axial and mirror symmetry of the drop, the expansion must be φ-independent, and consist only of m = 0 and even = 2j modes, where j is a non-negative integer.…”

Section: Exact Equilibrium Drop Shapesmentioning

confidence: 99%

Dynamics of ferrofluid drop deformations under spatially uniform magnetic fields

2016

View full text Add to dashboard Cite

We systematically study the shape and dynamics of a Newtonian ferrofluid drop immersed in an immiscible, Newtonian and non-magnetic viscous fluid under the action of a uniform external magnetic field. We obtain the exact equilibrium drop shapes for arbitrary ferrofluids, characterize the extent of deviations of the exact shape from the commonly assumed ellipsoidal shape, and analyse the smoothness of highly curved tips in elongated drops. We also present a comprehensive study of drop deformation for a Langevin ferrofluid. Using a computational scheme that allows fast and accurate simulations of ferrofluid drop dynamics, we show that the dynamics of drop deformation by an applied magnetic field is described up to a numerical factor by the same time scale as drop relaxation in the absence of any magnetic field. The numerical factor depends on the ratio of viscosities and the ratio of magnetic to capillary stresses, but is independent of the nature of the ferrofluid in most practical cases.

show abstract

Section: Exact Equilibrium Drop Shapesmentioning

confidence: 99%

Dynamics of ferrofluid drop deformations under spatially uniform magnetic fields

2016

View full text Add to dashboard Cite

show abstract

“…Plasma streamers excited in bubbles that are attached to the driving electrode ha:e been observed to result in resonant wave structure on the bubble surface [32]. The degree of electric field influence at the boundary is characterized by the electrical Weber number [35], which is the ratio of the applied electric field pressure to the surface tension stress,…”

Section: The Multiphase Streamermentioning

confidence: 99%

Plasma formation in underwater gas bubbles

Sommers¹,

Foster²

2014

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

The generation of plasma in underwater gas bubbles offers the potential to produce large volume plasma in water while minimizing electrode erosion. Such attributes are desirable for the design of plasma-based water purification systems. In this work, gas bubbles of diameter 0.4-0.7 mm were trapped in the node of a 26.4 kHz underwater acoustic standing wave and pulsed with voltages in the range 10-14 kV. Plasma formation in trapped, isolated bubbles was observed to occur through two separate pathways: (1) plasma generated in the bubble through impact by a liquid streamer and (2) plasma generated in the bubble due solely to the applied electric field. The former case demonstrates the mechanism of so-called streamer hopping in which the discharge transitions from a water streamer to a gaseous surface streamer. Perturbations of the bubble's fluid boundary due to the streamer are also discussed.

show abstract

“…The electrical stress distorts the surface of the bubble when the electrical pressure is comparable to the inward restorative force of the bubble's surface tension. The magnitude of the distortion scales with the electrical Weber number [12],…”

Section: Imaging Of Streamers In Bubblesmentioning

confidence: 99%

Observations of electric discharge streamer propagation and capillary oscillations on the surface of air bubbles in water

Sommers¹,

Foster²,

Babaeva³

et al. 2011

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

The propagation of electric discharge streamers inside bubbles in liquids is of interest for the remediation of toxins in water and plasma-based surgical instruments. The manner of streamer propagation has an important influence on the production of reactive species that are critical to these applications. Streamer propagation along the surface of electrode-attached bubbles of air in water, previously predicted by numerical simulations, has been experimentally imaged using a fast frame-rate camera. The successive pulsing of the streamer discharge inside the bubbles produced oscillations along the air-water interface. Subsequent streamers were observed to closely follow surface distortions induced by such oscillations. The oscillations likely arise from the non-uniform perturbation of the bubble driven by the electric field of the streamer and were found to be consistent with Kelvin's equation for capillary oscillations. For a narrow range of applied voltage pulse frequencies, the oscillation amplitude increased over several pulse periods indicating, potentially, resonant behaviour. We also observed coupling between bubbles wherein oscillations in a second bubble without an internal discharge were induced by the presence of a streamer in a fixed bubble.

show abstract

Critical strength of an electric field whereby a bubble can adopt a steady shape

Cited by 8 publications

References 12 publications

Dynamics of ferrofluid drop deformations under spatially uniform magnetic fields

Dynamics of ferrofluid drop deformations under spatially uniform magnetic fields

Plasma formation in underwater gas bubbles

Observations of electric discharge streamer propagation and capillary oscillations on the surface of air bubbles in water

Contact Info

Product

Resources

About