Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Flow in the Heart
Few flows are more integral to our well-being than blood flow through the heart. Over the course of our lives, our hearts develop from a few cells pushing viscous blood through tiny arteries to the muscular center of a vast circulatory network, capable of powering us through incredible physical feats. What’s most astonishing about all…
Forming an Oxbow
Without human intervention, meandering rivers become more sinuous over time. This is driven by the flow around a river bend, which tends to push sediment from the outer bank of the curve to the inner, making the bend more pronounced. Eventually, loops in the river can pinch off and form a separate oxbow lake, as…
Swallowing Physics
Swallowing – whether of food, beverage, or medication – is an important process for humans, but it’s one many struggle with, especially as they age. To help study the physics behind swallowing, one research group has built an artificial mouth and throat model, shown in the bottom row of images. The model uses rollers to…
Swirling Polygons
We don’t usually think of fluids forming corners, but they can. Here you see liquid nitrogen in a simple pot. Since the pot is much hotter than the boiling point of the nitrogen, the liquid nitrogen is floating on a layer of its own vapor. This is called the Leidenfrost effect. That nearly frictionless contact…
Powdery Trails
Because air and water are colorless and transparent, we cannot see most of the flows around us – but they’re always there. In a recent series, photographer Jess Bell has been capturing images of jumping dogs trailing a colorful powder wake. There’s no compositing in the photos. Bell puts powder on the dogs, then photographs…
Hydraulic Jumps
Chances are that you’ve seen plenty of hydraulic jumps in your life, whether they were in your kitchen sink, the whitewater of a river, or at the bottom of a spillway. Practical Engineering has a great primer on this oddity of open channel flow. When water (or other liquids) flow with a surface open to…
Amber Waves
When I was a teenager, I liked riding my bike along the river boardwalk near my house. There were fields there, like those in the image above and video below, with tall grass that would bend and sway in the wind. The long stalks undulated almost like a fluid, and they were mesmerizing. This video…
Exploding a Drop
Leidenfrost drops levitate over a hot substrate on a thin layer of their own vapor, constantly replenished as the drop evaporates. For the most part, previous studies have focused on pure droplets, but a new one looks at what happens when you add surfactants – and the results are, well, explosive. Surfactants are a type…
Inside Fondue
Cheese fondue is a complex – and delicious – Swiss delicacy. The perfect fondue requires the right mix of ingredients and preparation to get the rheology – the flow character – just right. Fondue is a colloid, a fluid containing a mixture of suspended insoluble particles. The major components, rheologically speaking, are fat globules and…
Collective Motion: Nematodes
We often imagine that collective motion creates an advantage – that the schooling fish and flocks of birds gain something from this behavior – but that’s not always the case. Above, you see nematodes moving through a thin liquid layer. Random collisions occasionally bring the nematodes into contact, and once that happens, surface tension holds…