Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Leapfrogging Vortices
This numerical simulation shows two pairs of vortices interacting in a leap-frogging motion. Another version shows the same situation but with a small perturbation in the rotational alignment that causes even more interesting interactions. Both simulations are of potential flow–an idealized flow without viscosity where velocity can be described as the gradient of a scalar…
Boiling in Microgravity
This week’s edition of the ISS research blog focuses on the Boiling Experiment Facility (BXF) and the goals of unlocking the secrets of boiling in microgravity. Without gravity to provide buoyant convection, boiling in space tends to produce one giant bubble instead of the hundreds of tiny ones we’re accustomed to seeing on our stoves.…
The Ekranoplan
The ekranoplan, the monster of the Caspian Sea, was a Soviet-era aircraft nearly 74 meters in length and weighing 380,000 kgs fully loaded. (In contrast, the C-17 is 53 m long and weighs 265,350 kg fully loaded.) This enormous craft relied on ground effect to stay aloft, where it was capable of 297 knots. Flying…
Jets from Waves
When vibrated, fluid surfaces can exhibit standing waves known as Faraday waves. In this experiment, increased forcing of these standing waves causes the formation of a jet. Under the right conditions, as the standing wave collapses, a singularity forms on the fluid surface when velocity and surface curvature diverge. The narrow jet column forms as…
Reynolds on Transition
For although only the disciplined motion is recognized in military tactics, troops have another manner of motion when anything disturbs their order. And this is precisely how it is with water: it will move in a perfectly direct disciplined manner under some circumstances, while under others it becomes a mass of eddies and cross streams,…
Volcanic Shock Waves
This footage of last year’s eruption of Eyjafjallajökull in Iceland shows shockwaves emanating from the mouth of the volcano as hot ash and gases explode from underground.
Laminar Flow Control
On Wednesday, March 30, 2011 at 3:00 EDT NASA engineers are holding an online chat about a current project to achieve laminar flow control on business jet-class airplanes. Keeping flow over an airplane’s wings laminar could decrease the total drag on an airplane by as much as 15%. In particular, this project involves placing tiny…
Computational Vortex Rings
Computational fluid dynamics (CFD) sometimes gets a bad rep as “colorful fluid dynamics”, but as computers get faster and faster, more complicated and physically accurate simulations are possible. Shown here are simulations of vortex rings and wingtip vortices in stunningly gorgeous detail. Understanding the evolution of these vortices from a fundamental level helps fluid mechanicians…
Solar Fluid Dynamics
The sun is a wild place fluid dynamically. The surface is riddled with convection cells the size of the Earth, and prominences of plasma (ionized gas) erupt from the surface following the sun’s magnetic field lines. Violent, but beautiful. #