Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Wrapping Rivulets
Tea lovers have long been frustrated by the tendency of liquid jets to adhere to solid surfaces – the so-called teapot effect that makes the last vestiges of every pour drip down the spout. By investigating the effect with vertical rods, researchers found that, at low enough flow rates, a liquid jet is able to…
Inside an Evaporating Drop
The evaporation of a simple droplet holds far more complexity than one would expect. If you look closely at the edge of the drop, there’s a tiny, beautiful display at work. It begins with small variations in surface tension at the contact line where solid, liquid, and gas meet. These could be caused by local…
How Rain Can Spread Pathogens
Rainfall can help spread pathogens from an infected plant to healthy ones. This transfer can happen both through droplets and by dry-dispersal of pathogen spores (top). When a raindrop hits a leaf, its initial spread triggers a vortex ring of air that can lift thousands of dry spores into a swirling trajectory (bottom). That boost…
Fighting Resonance
Resonance is a funny creature, as Dianna discovered when she tried to sing a rising scale through a tube. At certain notes, everyone who attempted to do it had their voices crack. Tracking down the source of the mystery means digging into what exactly resonance is and what the differences are between driving a system…
Plant Week: Bunchberry Dogwood
The bunchberry dogwood, unlike its taller relatives, is a low-lying subshrub that spreads along the ground. But it sports some of the fastest action of any plant, requiring 10,000 frames per second to capture! When young buds form in the bunchberry flower, their four petals are fused, completely hiding the stamens. As the plant matures,…
Plant Week: Citrus Jets
Bartenders and citrus lovers the world over are familiar with the mist of oil that bursts from a bent citrus peel. These microjets are about the width of a human hair, but they can spray at nearly 30 m/s in some citrus species. That’s an acceleration g-force of more 5,100, comparable to a bullet fired…
Plant Week: Jumping Spores
You might think that plants are pretty stationary, but they have evolved a myriad of ways of moving, especially when it comes to spreading their seeds and spores. Shown above is the spore of the horsetail plant, a spherical pod with four, ribbon-like elators that are moisture-sensitive. When exposed to water, the elators curl around…
Plant Week: Bladderworts
Carnivorous plants live in nutrient-poor environments, where clever techniques are necessary to keep their prey from getting away. The aquatic bladderwort family nabs their prey through ultra-fast suction. This starts with a slow phase (top) in which water is pumped out of the trap. Because the internal pressure is lower than the external hydrostatic pressure,…
Plant Week: Dandelions in Flight
To kick off Plant Week here on FYFD, we’re taking a closer look at that ubiquitous flower: the dandelion. Love ‘em or hate ‘em, these little guys manage to get just about everywhere, thanks in part to their amazing ability to stay windborne for up to 150 km! To do that, the dandelion uses a bristly umbrella…
Plant Week: Introduction
Spring has sprung! The trees have leaves, the flowers are in bloom, and snow is (almost) a distant memory.* And here at FYFD, we’re getting ready to kick off a full week of celebrating the intersection of fluid dynamics and plants. To get you into the mood, here’s a look at some previous plant-filled posts:…