Flutter is a rather innocuous term for a potentially dangerous phenomenon that can occur for any flexible structure in a moving flow. Aeroelastic flutter occurs when aerodynamic forces and a structure’s natural Keep reading
Month: March 2025
Transition to Turbulence
Smoke introduced into the boundary layer of a cone rotating in a stream highlights the transition from laminar to turbulent flow. On the left side of the picture, the boundary Keep reading
High-Speed Ferrofluid
High-speed video captures the behavior of a ferrofluid trapped between two magnets. Ferrofluids contain tiny ferromagnetic particles suspended in a carrier fluid like oil or water. The distinctive peaks and Keep reading
Diesel Ignition
In a diesel engine, ignition of the injected fuel occurs due to the heat caused by the compression of the fuel/air mixture. (In petrol/gasoline engines, spark plugs are used for Keep reading
Playing Pac-Man with Water Droplets
The vibrations of a plate in the horizontal and vertical directions can be used to control the motion of a drop placed on the surface. Here a droplet of water Keep reading
Viscous Fingers
A Hele Shaw cell is little more than two glass plates separated by a thin layer of viscous fluid. The cell serves as a good test bed for viscous, low Reynolds number Keep reading
Visualizing Fish Wakes
This novel flow visualization technique uses dilute solutions of the tobacco mosaic virus (TMV). These rod-shaped particles align with shear and produce a birefringent interference pattern visible when viewed between Keep reading
The Disintegrating Bowl
A viscous fluid droplet impacts a thin layer of ethanol, which has a lower surface tension than the viscous fluid. A spray of tiny ethanol droplets is thrown up while Keep reading
Mapping Flames
Combustion remains a fascinating and only partially understood phenomenon. Here scientists work to map a flame in three dimensions using high-speed cameras and digital reconstruction. (submitted by Chi M)
Making Waves
A standing wave is created in a wave tank by fixing a wall at one end and moving the other wall–the wave generator–at a frequency such that the outgoing waves Keep reading