Fuck Yeah Fluid Dynamics

This video explores some of the physics behind the much-loved bursting water balloon. The first sections show some “canonical” cases—dropping water balloons onto a flat rigid surface.  In some cases the balloon will bounce and in others it breaks. The bursting water balloons develop strong capillary waves (like ripples) across the upper surface and have some shear-induced deformation of the water surface as the rubber peals away. Then the authors placed a water balloon underwater and vibrated it before bursting it with a pin. They note that the breakdown of the interface between the balloon water and surrounding water shows evidence of Rayleigh-Taylor and Richtmyer-Meshkov instabilities. The Rayleigh-Taylor instability is the mushroom-like formation observed when stratified fluids of differing densities mix, while the Richtmyer-Meshkov instability is associated with the impulsive acceleration of fluids of differing density.

(Source: arxiv.org)

Playing with a giant water balloon and high-speed cameras is like a giant experiment in surface tension, right up until the tensile strength of the balloon comes into play. The rippling in the balloon is reminiscent of the motion of droplet breakup or impact on superhydrophobic surfaces. (submitted by Daniel B)

While this video is not strictly about fluid dynamics, there are some pretty cool high-speed fluids moments in it. Watch the reaction of the gelatins as objects hit them and observe the deformation of the water balloons as they strike. (via JetForMe)

(Source: stumbleupon.com)

While not strictly fluid mechanical Philip Heron’s Tempus II features some great slow-motion action of fluids. (via @ftematt)

Sometimes you need microgravity in order to observe the neat effects of surface tension on a fluid. Also, I hear it’s a good excuse for popping water balloons on the Vomit Comet. #