Why do bubbles in champagne form in orderly rising chains from specific spots on the glass, and what determines the bubbling rate?
#fluid-dynamics
Post a problemWhy is the popular 'teardrop' cartoon shape of a falling raindrop physically wrong, and what shape do real raindrops actually take?
Why do wet mammals from mice to bears shake themselves dry at a frequency that scales in a simple, predictable way with their body size?
How does a pop-pop boat, which only pulses water in and out of a rear nozzle with no net average flow, manage to move forward continuously?
Why does a thin, fast vertical jet of water shoot upward after the air cavity created by a falling ball or drop collapses beneath the surface?
A person wearing perfume enters a lecture hall; roughly how long does it take before someone across the room can smell it, and does ordinary molecular diffusion explain the timescale?
Why does a spilled drop of coffee (or red wine) dry into a dark ring around the outside with a pale center, instead of leaving an evenly colored stain?
Why does a plastic shower curtain often billow inward toward the water spray and stick to your legs while you shower, instead of staying put or blowing outward?
Contrary to the classic cartoon teardrop symbol, what shape does a falling raindrop actually have, and why isn't it pointed at the top?
Why does the water pressure, and hence the total force, on the bottom of a container depend only on the height of the water column and the base area — not on the container's shape or the total weight of water inside it — so that a narrow vase can press on its base just as hard as, or harder than, a…
Why do raindrops in a storm follow a characteristic size distribution -- many small drops, few large ones -- as described empirically since the 1940s?
Why do ship wakes on deep water always form a V of the same angle (about 19.5 degrees) regardless of the ship's speed, and do very fast ships obey this?
Can a levitating Leidenfrost droplet be made to move in a controlled direction using a ratchet-textured hot surface?
How can the basilisk ('Jesus Christ') lizard run across the surface of open water without sinking?
Why can a water droplet levitating on its own vapor cushion above a very hot surface spontaneously start oscillating into a rotating star-like polygonal shape?
Why do some smooth, spinning balls at intermediate speeds curve in the direction opposite to what the ordinary Magnus effect predicts?
Why does a thinning thread of a polymer or viscoelastic fluid form a regular string of beads instead of smoothly pinching off into a single drop?
Why can small insects and water striders walk on water using surface tension, while this same strategy becomes impossible for animals much larger than about a human hand?
Why can pathogen-laden droplets from a sneeze or cough travel much farther than the classical 1930s evaporation-falling-curve models predicted?
Is there a theoretical model that can predict the statistical structure of turbulent flow (e.g. energy distribution across eddy sizes) directly from the Navier-Stokes equations, without ad hoc empirical closures?