The time evolution equation of motion and shape are derived for a self-propelled droplet driven by a chemical reaction. The coupling between the chemical reaction and motion makes an inhomogeneous concentration distribution as well as a surrounding flow leading to the instability of a stationary state. The instability results in spontaneous motion by which the shape of the droplet deforms from ...

The deformation of a viscous liquid droplet suspended in another liquid and subject to an applied electric field is a classic multiphase flow problem best described by the Melcher–Taylor leaky dielectric model. The main assumption of the model is that any net charge in the system is concentrated on the interface between the two liquids as a result of the jump in Ohmic currents from the bulk. Up...

A tightly focused laser beam exerting a trapping force on an object also exerts deformation forces on the object. If the object is relatively easy to deform, as is, e.g., a low surface tension droplet, the resulting deformation is easily detectable even at moderate laser powers. The observed deformation is analytically explained by a model, which quantitatively predicts the deformation of any m...

Surfaces may be rendered superhydrophobic by engineering the surface morphology to control the extent of the liquid-air interface and by the use of low-surface-energy coatings. The droplet state on a superhydrophobic surface under static and dynamic conditions may be explained in terms of the relative magnitudes of the wetting and antiwetting pressures acting at the liquid-air interface on the ...

A finite-element model has been developed to predict the evolution of temperature, stress, and shape of 10-mm diameter molten steel droplets solidifying against a water-cooled copper chill plate. The elastic-viscoplastic stress model accounts for thermal linear expansion / contraction behavior, creep, and phase transformations that vary with carbon content. Thermal contraction causes the quench...

Abstract To analyze the complex droplet transient deformation involving two immiscible phases, a practical multi-interfacial tension model has been introduced in SPH framework. The attraction, which operates on interface between different phases is explicitly defined as London dispersion force using Fowkes theoretical model, and interfacial can be calculated sum of attraction magnitudes corresp...

A unique approach to simulate mass transfer across the moving droplet where mass transport equations and governing equations of the levels set method are solved separately is proposed in this work. Mass transfer coefficients of the chemical species can be computed by equating the diffusive flux and the mass transfer flux at the interface, which are found to be of the same order of magnitude as ...

We experimentally study the interaction of intense laser pulses with metallic microdroplets and resulting deformation. Two main droplet deformation regimes have previously been established: that sheet-type expansion after impact “long” (typically >10 ns) governed by incompressible flow spherical internal cavitation “short” <100 ps) shock waves, i.e., strongly compressible flow. In this wo...