Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
The Kaye Effect
Those who have poured viscous liquids like syrup or honey are familiar with how they stack up in a rope-like coil, as shown in the top row of images above. What is less familiar, thanks to the high speed at which it occurs, is the Kaye effect, which happens in fluids like shampoo when drizzled.…
Kelvin’s Thunderstorm
In this video, Derek Muller explains how an experiment known as Lord Kelvin’s thunderstorm generates electricity from falling water. The set-up relies on a positive feedback loop that creates a separation of charge between the two streams of water. Check out the video for a great demonstration and explanation. If you prefer your science with a…
Inside the Strait of Gibraltar
When a fluid is stratified into layers, it’s possible to have waves generated and transmitted along the interface between layers. Because these waves remain inside the bulk fluid, they are called internal waves. They often occur in the atmosphere or the ocean as fluids with different properties move past changing terrain. The Strait of Gibraltar…
Levitating Droplets with Motion
There are many ways to levitate a droplet – heating, vibration, and acoustic levitation all come to mind – but this video demonstrates a simpler method: a moving wall. Depositing a drop on a moving wall keeps it aloft with a thin, constantly replenished layer of air. The thickness of this lubricating air film is…
The Marangoni Effect
Differences in surface tension can create Marangoni flow along an interface. Imagine a shallow bowl filled with a liquid. In the middle of the fluid, every molecule is surrounded on all sides by like molecules, which push and pull it equally in all directions. But at the surface, the fluid molecules are only acted on…
Plume Stratification
Clean-up of accidents like the 2010 Deepwater Horizon oil spill can be complicated by what goes on beneath the ocean surface. Variations in temperature and salinity in seawater create stratification, stacked layers of water with differing densities. When less dense layers are on top, the fluid is said to be stably stratified. Since oil is less…
Bounce or Freeze?
Icing is a major problem for aircraft. When ice builds up on the leading edge of a wing it creates major disruptions in flow around the wing and can lead to a loss of flight control. One of the important factors in predicting and controlling ice building up is knowing when and where water droplets will…
“Cymatic Sun”
“Cymatic Sun” from artist Lachlan Turczan uses vibrating fluids to generate mesmerizing and surreal visuals. At some points distinct Faraday waves are visible on the surface. At other times, there is simply a blur of motion and refracted light. Check out my “fluids as art” tag for many more great examples of fluid dynamics and…
Shooting Droplets with Lasers
Last week we saw what happens when a solid projectile hits a water droplet; today’s video shows the impact of a laser pulse on a droplet. Several things happen here, but at very different speeds. When the laser impacts, it vaporizes part of the droplet within nanoseconds. A shock wave spreads from the point of impact and…
Meandering Rivulet
This rivulet is the result of a horizontal liquid jet impacting a vertical pane of glass. Gravity, surface tension, adhesion, and even surface finish can affect the path the water follows. Like the meandering path of rain on a windshield, it’s hard to predict a priori where the flow will go without accounting for a…