Hospital-acquired infections are a serious health problem. One potential source of contamination is through the spread of pathogen-bearing droplets emanating from toilet flushes. The video above includes high-speed flow visualization Keep reading
Month: December 2023
Bubbles Through Constrictions
Surface tension usually constrains bubbles to the smallest area for a given volume – a sphere – but sometimes other forces generate more complicated geometries. The images above show bubbles Keep reading
Pathlines vs. Streaklines
When considering fluid motion, there are many ways to describe trajectories through the flow. One is the pathline, the trajectory followed by an individual fluid particle. Imagine releasing a rubber Keep reading
Bouncing Off The Surface
For the right angles and flow rates, it’s possible to bounce a fluid jet off a pool of the same fluid. As the jet flows, it pulls a thin layer Keep reading
Liquid Crystal Films
Smectic liquid crystals can form extremely thin films, similar to a soap bubble, that are sensitive to electrically-induced convection. Here an annular smectic film lies between two electrodes. When a Keep reading
APS DFD etc.
It’s time! The American Physical Society’s Division of Fluid Dynamics meeting opens in Pittsburgh tomorrow morning. It promises to be a very busy few days. Most of that activity will Keep reading
Start Your Rocket Engine
When supersonic flow is achieved through a wind tunnel or rocket nozzle, the flow is said to have “started”. For this to happen, a shock wave must pass through, leaving Keep reading
The Glory of a Roll Cloud
Roll clouds stretch like a long horizontal tube, spinning as they process across the sky. This class of arcus cloud is relatively rare but occasionally forms in areas where cool Keep reading
Shocked Interfaces
The Richtmyer-Meshkov instability occurs when two fluids of differing density are hit by a shock wave. The animation above shows a cylinder of denser gas (white) in still air (black) before being hit Keep reading
The Challenges of Trapping Carbon Dioxide
One way to reduce carbon dioxide in the atmosphere is to pump the CO2 into saline aquifers deep below the surface. Such aquifers are thin but stretch over large areas Keep reading