Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Extinguishing Flames
Putting out fires can be a difficult, water-intensive task. In this video, scientists demonstrate how using a non-Newtonian fluid can make it easier to extinguish and suppress flames. Where water tends to splatter and scatter against an object, a yield-stress fluid can cling and coat to smother the flame. The fluid used here is water…
Pollock-Style Physics
Here on FYFD, we like to show off the artistic side of fluid dynamics. But some researchers are actively studying how artists use fluid dynamics in their art. In this video, they examine one of Jackson Pollock’s painting techniques, in which filaments of paint were applied by flinging paint off a paintbrush. Getting the technique…
Early Rocket Launch
Pre-dawn launches provide some of the most dramatic rocket footage. This video is from an October 2nd Atlas V launch, and the really fun stuff starts at about 0:34. As the rocket climbs to higher altitudes, the atmospheric pressure around it decreases. As a result of this low pressure, the rocket’s exhaust gases balloon outward…
Shock Diamonds
Rocket engine exhaust often contains a distinctive pattern known as shock diamonds or Mach diamonds. These are a series of shock waves and expansion fans that increase and decrease, respectively, the supersonic exhaust gases’ pressure until it equalizes with atmospheric pressure. The bright glowing spots visible to the naked eye are caused by excess fuel…
Un-Mixing a Flow
This video demonstrates one of my favorite effects: the reversibility of laminar flow. Intuition tells us that un-mixing two fluids is impossible, and, under most circumstances, that is true. But for very low Reynolds numbers, viscosity dominates the flow, and fluid particles will move due to only two effects: molecular diffusion and momentum diffusion. Molecular…
Flowing Water on Mars?
Scientists have known for years that Mars once had liquid water on its surface, and they have many contemporary examples of frozen water ice on the Red Planet. But this week NASA announced the strongest evidence yet that liquid water still flows on Mars. Researchers have observed from orbit dark line-like features called recurring slope…
Healing Soap Films
As fragile as a soap bubble seems, these films have remarkable powers of self-healing. The animation above shows a falling water droplet passing through a soap film without bursting it. An important factor here is that the water droplet is wet–passing a dry object through a soap film is a quick way to burst it,…
Phytoplankton Bloom
This incredible false-color satellite image shows a cyanobacteria phytoplankton bloom in the Baltic Sea. The image is roughly 900 km across and is beautifully detailed. Check out the full resolution version. The tiny phytoplankton act like tracer particles in the flow, sketching out the massive whorls as well as the tiny lacy wisps that make…
Sandscapes
Many of us have played with sand art–the rotating frames filled with water, sand, and air. In this video, Shanks FX demonstrates some of the realistic and surrealistic landscapes you can create using this toy. It also makes for a neat fluid dynamics demonstration. The buoyancy of the trapped air bubbles lets the sand sift…
Self-Pouring Fluids
Non-Newtonian fluids are capable of all kinds of counter-intuitive behaviors. The animations above demonstrate one of them: the tubeless or open siphon. Once the effect is triggered by removing some of the liquid, the fluid quickly pours itself out of the beaker. This is possible thanks to the polymers in the liquid. The falling liquid…