Related papers: Ferrofluid Droplet Behavior on Gradient Surfaces I…
In a recent Letter (Y. Sumino et al., PRL 94, 068301 (2005)) a spontaneous motion of an oil droplet in the surrounding aqueous media along a glass surface was reported. The authors suggested that the self-locomotion is driven by a…
The impact of droplets on an inclined falling liquid film is studied experimentally using high-speed imaging. The falling film is created on a flat substrate with controllable thicknesses and flow rates. Droplets with different sizes and…
It is widely thought that in steady, gravity-driven, unobstructed soap-film flows, the velocity increases monotonically downstream. Here we show experimentally that the velocity increases, peaks, drops abruptly, then lessens gradually…
We demonstrate \textit{bendotaxis}, a novel mechanism for droplet self-transport at small scales. A combination of bending and capillarity in a thin channel causes a pressure gradient that, in turn, results in the spontaneous movement of a…
In this study, an enthalpy-based lattice Boltzmann flux solver is developed to simulate the freezing dynamics of a ferrofluid droplet under a uniform magnetic field. The accuracy and robustness of the solver are first validated through…
Janus particles self-propel by generating local tangential concentration gradients along their surface. These gradients are present in a thin layer whose thickness is small compared to the particle size. Chemical asymmetry along the surface…
Swimming droplets are a class of active particles whose motility changes as a function of time due to shrinkage and self-avoidance of their trail. Here we combine experiments and theory to show that our non-Markovian droplet (NMD) model,…
The impact dynamics of spinning droplets onto superhydrophobic surfaces was studied by using Volume-of-Fluid simulations, covering broad ranges of Weber number ($We$) and dimensionless angular velocity ($\mathit{\Omega}$). The omputational…
Ferrofluids, composed of magnetic nanoparticles suspended in a non-magnetic carrier liquid, have attracted considerable attention since their discovery in the 1960s. Their combination of liquid and magnetic properties gives rise to complex…
The effect of a spatially uniform magnetic field on the shear rheology of a dilute emulsion of monodispersed ferrofluid droplets, immersed in a non-magnetizable immiscible fluid, is investigated using direct numerical simulations. The…
How to make small liquid droplets move spontaneously and directionally on solid surfaces is a challenge in lab-on-chip technologies, DNA analysis, and heat exchangers. The best-known mechanism, a wettability gradient, does not move droplets…
We report spontaneous motion in a fully bio-compatible system consisting of pure water droplets in an oil-surfactant medium of squalane and monoolein. Water from the droplet is solubilized by the reverse micellar solution, creating a…
We study the deterministic dynamics of single-domain ferromagnetic nanoparticles in a viscous liquid induced by the joint action of the gradient and uniform magnetic fields. It is assumed that the gradient field depends on time harmonically…
A mean-field Fokker-Planck equation approach to the dynamics of ferrofluids in the presence of a magnetic field and velocity gradients is proposed that incorporates magnetic dipole-dipole interactions of the colloidal particles. The model…
In the present work the instability of a flat horizontal thin layer of a magnetic fluid (the depth of no more than 50 \mum) under the action of a uniform magnetic field is studied experimentally. It was revealed that the development of…
Fluid instabilities are ubiquitous phenomena of great theoretical and applied importance. In particular, an intriguing example is the thermocapillary or B\'enard-Marangoni instability which occurs when a thin horizontal fluid layer, whose…
Brownian motion (BM) is pivotal in natural science for the stochastic motion of microscopic droplets. In this study, we investigate BM driven by thermal composition noise at sub-micro scales, where inter-molecular diffusion and surface…
We study the spreading of droplets in a near-critical phase-separated liquid mixture, using a combination of experiments, lubrication theory and finite-element numerical simulations. The classical Tanner's law describing the spreading of…
This study presents a novel and user-friendly technique for detecting the lateral capillary force on a floating spherical particle. The technique leverages the interplay between the capillary attracting forces, hydrostatic pressure forces,…
When a liquid droplet impacts a hot solid surface, enough vapor may be generated under it as to prevent its contact with the solid. The minimum solid temperature for this so-called Leidenfrost effect to occur is termed the Leidenfrost…