Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Frost on Superhydrophobic Surfaces
Frost formation and ice adhesion on superhydrophobic surfaces For anyone with further interest in the ice formation on superhydrophobic surfaces story we posted recently, the published paper is currently offered by AIP for free. #
Reader Question: Swimming and Buoyancy
aniiika asks: How does buoyancy relate to swimming? Buoyancy is the force that enables a swimmer to float in the water, even when still. Buoyant force is equal to the weight of the fluid displaced by the swimmer; in other words, the density of the fluid multiplied by the volume of the swimmer that is…
Chaos in Suspension
In science, the term chaotic is used to describe a system whose behavior is highly sensitive to initial conditions. This means that the end state can vary widely based on small changes at the start–also commonly known as the butterfly effect. Many fluid dynamical systems are chaotic, especially turbulent ones. Above are a series of…
Levitating Liquid Oxygen
The Leidenfrost effect occurs between a fluid and a solid of vastly different temperatures. In the case of liquid oxygen, a thin layer of the oxygen vaporizes on contact with the room temperature solid, leaving a droplet of liquid oxygen to float along on its own vapor. Oxygen droplets are paramagnetic, meaning that they are…
Vibrating Fluid Interfaces
The Faraday instability forms when a fluid interface is vibrated. This high-speed video shows the differences in the shapes formed by a vibrated fluid interface when the two fluids are miscible–capable of mixing–and when they are immiscible–like oil and water. Note how the miscible interface breaks down quickly into turbulence, but the immiscible interface maintains…
Colorful Computational Combustion
Many fluid dynamics problems are so complicated that they require supercomputers to calculate the mathematical and physical details. This image shows a computer simulation of a cold ethylene jet combusting in hot air. Different colors indicate different combustion by-products. Researchers use simulations like this one to investigate ideal flames that improve efficiency in applications like…
Plasma Demo
This neat magnetohydrodynamic (MHD) demo is one we do not suggest repeating at home. The high voltage applied across the magnets and the plate causes the white disk in between to vaporize and form a plasma. Then the magnetic field causes the circumferential motion via the Lorentz force, essentially trapping the plasma and making it spin.
Turbulent Phytoplankton Eddies
Where warm and cold ocean currents collide, turbulent eddies form and pull up valuable nutrients from the ocean floor. Massive phytoplankton blooms ensue, effectively providing natural flow visualization for the process. #
DIY Solutal Convection
In this video, the HouseholdHacker heads to the kitchen and uses milk, food coloring, and dish soap to create some solutal convection much like this one with cream and liqueur. The food coloring serves as a tracer for the fluid motion; it’s really the interaction of the milk and the dish soap that drives the…
Marangoni Convection in Space
In this Saturday Morning Science video, astronaut Don Pettit demonstrates Marangoni convection in microgravity using a water film with tracer particles, a soldering iron, and a flashlight. This same effect occurs on earth but is masked behind the much stronger effect of buoyant convection.