When a droplet is gently laid onto the surface of the same liquid, it stays at rest for a moment before coalescence. The coalescence can be delayed and sometimes inhibited by injecting fresh air under the droplet. This can happen when the surface of the bath oscillates vertically. In this case the droplet basically bounces on the interface. The lifetime of the droplet has been studied with resp...

This paper presents the experimental results and analyses on a controlled manipulation of liquid droplets upon local reduction and oxidation (redox) of a smart polymer-dodecylbenzenesulfonate doped polypyrrole (PPy(DBS)). The electrochemically tunable wetting property of PPy(DBS) permitted liquid droplet manipulation at very low voltages (-0.9 to 0.6 V). A dichloromethane (DCM) droplet was flat...

Droplets deform soft substrates near their contact lines. Using confocal microscopy, we measure the deformation of silicone gel substrates due to glycerol and fluorinated-oil droplets for a range of droplet radii and substrate thicknesses. For all droplets, the substrate deformation takes a universal shape close to the contact line that depends on liquid composition, but is independent of dropl...

This paper describes the break-up of droplets in a concentrated emulsion during its flow as a 2D monolayer in a microchannel consisting of a narrow constriction. Analysis of the behavior of a large number of drops (N > 4000) shows that the number of break-ups increases with increasing flow rate, entrance angle to the constriction, and size of the drops relative to the width of the constriction....

In this research, the maximum deformation ratio of water-based paint droplets impacting and spreading onto a flat solid surface was investigated numerically based on the Navier–Stokes equation coupled with the level set method. The effects of droplet size, impact velocity, and equilibrium contact angle are taken into account. The maximum deformation ratio increases as droplet size and impact ve...

The behaviour of a single droplet in an immiscible external fluid, submitted to shear flow is investigated using numerical simulations. The surface of the droplet is modelled by a Boussinesq–Scriven constitutive law involving the interfacial viscosities and a constant surface tension. A numerical method using Loop subdivision surfaces to represent droplet interface is introduced. This method co...

The Taylor analogy breakup (TAB) model is used for the prediction of drop deformation and drop breakup in spray simulations conducted with CFD codes. This model assumes that a spherical droplet moving in a gas stream behaves like a forced, damped harmonic oscillator in which the forcing term is given by the aerodynamic drag, the damping is due to the liquid viscosity and the restoring force is ...

We report on the experimental studies of the deformation and fragmentation of liquid metal droplets by picosecond and subpicosecond laser pulses. The experiments were performed with laser irradiance varying in 10-10 W/cm range. The observed evolution of the droplet shape upon the impact dramatically differs from the previously reported for nanosecond laser pulses. Instead of flattening the drop...