Related papers: Impact force reduction by consecutive water entry …
The forces on an object impacting the water are extreme in the early moments of water entry and can cause structural damage to biological and man-made bodies alike. These early-time forces arise primarily from added mass, peaking when the…
A 'splash' is usually heard when a solid body enters water at large velocity. This phenomena originates from the formation of an air cavity resulting from the complex transient dynamics of the free interface during the impact. The classical…
In this study, we experimentally examine the behavior of a free-falling rigid sphere penetrating a quiescent liquid pool. Observations of the sphere trajectory in time are made using two orthogonally placed high-speed cameras, yielding the…
This study experimentally examines the entry and penetration of a superhydrophobic sphere into a quiescent deep pool, with special emphasis placed on the primary and secondary pinch-off of the air cavity existing in its wake. Two aspects…
The transient cavity dynamics during water entry of a heavy, non-rotating sphere impacting a rotating pool of liquid is studied experimentally, numerically, and theoretically. We show that the pool rotation advances the transition of the…
The hydrodynamics associated with water-entry of spheres can be highly variable with respect to the material and kinematic properties of the sphere. This series of five fluid dynamics videos illustrates several subtle but interesting…
When a rigid body collides with a liquid surface with sufficient velocity, it creates a splash curtain above the surface and entrains air behind the sphere, creating a cavity below the surface. While cavity dynamics have been studied for…
A falling liquid drop, after impact on a rigid substrate, deforms and spreads, owing to the normal reaction force. Subsequently, if the substrate is non-wetting, the drop retracts and then jumps off. As we show here, not only is the impact…
This research focuses on the water entry of spheres in the surface seal regime. Herein, surface seal occurs in the wake of a sphere impact with the water surface and is characterized by splash dome over and cavity pull-away between the…
We make time resolved velocity measurements of steel spheres in free fall through liquid using a continuous ultrasound technique. We explore two different ways to induce large changes in drag on the spheres: 1) a small quantity of…
When a blunt body impacts an air-water interface, large hydrodynamic forces often arise, a phenomenon many of us have unfortunately experienced in a failed dive or "belly flop." Beyond assessing risk to biological divers, an understanding…
This fluid dynamics video shows the impact of a hydrophobic sphere impacting a water surface. The sphere has a mass ratio of m* = 1.15, a wetting angle of 110 degrees, a diameter of 9.5 mm, and impacts the surface with a Froude number of Fr…
The impact of droplets on a liquid pool is ubiquitous in nature and important in many industrial applications. A droplet impacting on a liquid pool can result in the pinch-off of a regular bubble or entrap a large bubble under certain…
A drop impacting a solid surface with sufficient velocity will emit many small droplets creating a splash. However, splashing is completely suppressed if the surrounding gas pressure is lowered. The mechanism by which the gas affects…
The water entry of solid and liquid bodies has been studied for over a century, and various researchers have classified the different behaviors that occur when the gas-filled cavity collapses. Although four main cavity collapse regimes have…
A tiny air bubble can be entrapped at the bottom of a solid sphere that impacts onto a liquid pool. The bubble forms due to the deformation of the liquid surface by a local pressure buildup inside the surrounding gas, as also observed…
We explore a surprising phenomenon in which an obstruction accelerates, rather than decelerates, a moving flexible object. It has been claimed that the right kind of discrete chain falling onto a table falls \emph{faster} than a…
We perform numerical simulations to study the dynamics of the entry of hydrophobic spheres in a pool of water using ANSYS. To track the air-water interface during the translation of the sphere in the pool of water, we use the volume of…
Diving induces large pressures during water entry, accompanied by the creation of cavity and water splash ejected from the free water surface. To minimize impact forces, divers streamline their shape at impact. Here, we investigate the…
We investigate the impact of a free-falling water drop onto a granular layer. First, we constructed a phase diagram of crater shapes with two control parameters, impact speed and grain size. A low-speed impact makes a deeper cylindrical…