We study the coalescence of two drops of an ideal fluid driven by surface tension. The velocity of approach is taken to be zero and the dynamical effect of the outer fluid (usually air) is neglected. Our approximation is expected to be valid on scales larger than ℓ ν = ρν 2 /σ, which is 10nm for water. Using a high-precision boundary integral method, we show that the walls of the thin retractin...

The behaviour of a viscous drop squeezed between two horizontal planes (a Hele-Shaw cell) is treated by both theory and experiment. When the squeezing force $F$ constant surface tension neglected, predicts ultimate growth radius $a\sim t^{1/8}$ with time $t$ . This first reviewed found to be in excellent agreement Surface at boundary reduces interior pressure, this effect included analysis, alt...

Water motion is a highly complex phenomenon. From ocean waves to raindrops, water is described by a wide range of shapes and is affected by a wide range of forces. This paper presents a physically-based method of modeling the latter phenomenon raindrops. This model can handle bodies of water with varying underlying terrain, as well as many different fluids, but cannot represent spray systems, w...

We study experimentally the impact of liquid drops against thin plates pierced with small holes. When the drop is larger than the hole, different situations can occur: (i) at a small velocity, the drop is entirely captured by the plate; (ii) above a threshold speed, some liquid is ejected below the surface. We characterize this critical speed and these two different situations, focusing on the ...

He had lost his vision despite multiple surgical attempts over the years to save his sight. Darkness came out of his mouth, as he hurled foul language at me, while I tried to conduct a preoperative anesthesia interview and prepare him for yet another surgical procedure on his eyes. He was still stunned by a collective disappointment from his previous five corneal transplants that had failed. He...

The aim of this study was to assess whether patients have their ocular drops correctly prescribed during non-ophthalmic admissions to hospital. A retrospective review of notes of patients who were admitted to hospital for general medical or surgical care, while on regular eye drops at the time of admission was performed. Twenty two patients were on regular ocular medication when admitted. Only ...

Abstract We consider evaporation of pure liquid drops on a thermally conductive substrate. Two evaporative models are considered: one that concentrates on the liquid phase in determining evaporative flux, and the other one that centers on the gas/vapor phase. A single governing equation for the evolution of drop thickness, including both models, is developed. Experiments are used to estimate re...

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....

The use of microfluidic devices to control drops of water in a carrier oil is a promising means of performing biological and chemical assays. An essential requirement for this is the controlled coalescence of pairs of drops to mix reagents together. We show that this can be accomplished through electrocoalescence of drops synchronized by size-dependent flow in microfluidic channels. Smaller dro...