title: Single-mode instability of a ferrofluid-mercury interface under a nonuniform magnetic field.
abstract: This work reports an experimental and a numerical study of the interfacial instability in a mercury-ferrofluid system caused by a spatially nonuniform magnetic field against the action of gravity and interfacial tension. The interface evolution is observed to be continuous till its movement is hindered by a physical boundary. In contrast to the behavior of the ferrofluid interface under uniform field, we noted the instability growth to be monotonic under a field gradient. A steepness in the growth curve is noticed during the later stages of the instability, indicating a high magnitude of the growth velocities. Some unique phenomena, such as similarity of the growth at the initial stage, a slope transition in the growth curve at a later stage, and wrapping and pinning of the interface are observed, both in experiments and simulations.
authors: Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
authors: Chamkor
authors: C
authors: Singh
authors: Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, India.
authors: Arup K
authors: AK
authors: Das
authors: Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
authors: Prasanta K
authors: PK
authors: Das