Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Meteoroids
Meteoroids are debris from earlier eras in our solar system. They can be leftovers from planets that never formed or remains of ancient collisions. When these bits rock and metal enter our atmosphere, they become meteors. Since they travel at speeds of several kilometers per second, they create incredibly strong shock waves off their bow…
The Telstar 18
Every four years, Adidas creates a newly designed ball for the World Cup. This year’s version is the Telstar 18, which features six glued panels (no stitching!) with a slightly raised texture. That subtle roughness is an important feature for the ball’s aerodynamics. It helps ensure that flow around the ball will become turbulent at…
The Fluid Dynamical Sewing Machine
If you’ve drizzled viscous liquids like honey or syrup, you’ve no doubt witnessed their ability to coil. Combine that coiling with a moving platform and you form a system known as the fluid dynamical sewing machine, which creates different consistent patterns of loops and curves depending on the speed at which the liquid falls and…
Spinning Droplet Galaxies
Water flung from a spinning tennis ball takes on a shape reminiscent of a spiral galaxy. As it detaches, water leaves the surface with both the tangential velocity of the spinning ball and a radial velocity due to the centrifugal force flinging it. The continued spin of the ball makes the thin ligaments of water…
Flying Backwards
Spend a summer afternoon floating in a kayak and chances are you’ll see some impressive aerial acrobatics from dragonflies. One of the dragonfly’s superpowers is its ability to fly backwards, which helps it evade predators and take-off from almost any orientation. To do this, the dragonfly rotates its body so that it is nearly vertical,…
Craters and Rays
The history of our solar system is written in impact craters, but these craters have been remarkably mysterious for years. Scientists knew that you could recreate many of their features by dropping solid objects into granular materials like sand, but this did not produce the distinctive rays that we see around many real craters (bottom…
Lava Balls
View this post on Instagram #LeilaniEstatesEruption #KilaueaVolcano LATEST (June 27 at 8:15 PM): New unbelievable video from @IkaikaMarzo captures the phenomena that USGS has named a “lava boat”. Watch as it makes its way down the #Fissure8 lava river in Kapoho and then breaks apart ? • Dear @kalapanaculturaltours, I thought lava boats were for…
Vortex Ring Collisions
One of the most enduringly popular submissions I receive is T. Lim’s experimental footage of two vortex rings colliding head-on. It’s an devilishly tough experimental set-up to master because perfectly aligning the rings is incredibly difficult. The pay-off, however, is huge because the breakdown of the colliding rings and their transformation into secondary rings is…
2D Turbulence
Turbulence, the chaotic regime of fluid dynamics, is a complicated beast. It’s hard to analyze or predict, but we do understand some general ideas about it, like the fact that energy starts out in large eddies, cascades down smaller and smaller ones, and finally gets dissipated at the smallest scales, where viscosity snuffs them out.…
Visualizing Turbulence
Turbulence, the seemingly random and chaotic state that fluids often tend toward, can be difficult to wrap one’s head around. Turn your faucet on high or pour milk into your coffee, and the flow just looks like a completely unpredictable mess. But there are important patterns to be found.These flows have many different lengthscales and…