Is there a general theory that predicts the statistical behavior of turbulent fluid flow directly from the Navier-Stokes equations, and can fully chaotic dynamical systems be understood from first principles?
#fluid-dynamics
Post a problemA river's water speed varies with depth and distance from the banks; can an object floating freely on the surface ever travel downstream faster than the river's fastest-flowing water?
Why does liquid poured slowly from a teapot or measuring cup sometimes cling to and run down the outside of the spout instead of falling cleanly away as a free-falling stream (the 'teapot effect')?
How can water striders and similar insects stand and skate across the surface of a pond without breaking through, and how do they push themselves forward without solid ground to push against?
When skipping a flat stone across a pond, what throwing angle between the stone and the water surface gives the largest number of bounces, and why does that particular angle work best?
Is it true that the Earth's rotation (the Coriolis effect) makes bathtubs and sinks drain counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere, and if so, why don't ordinary home bathtubs reliably show this?
What physically produces the sharp popping sound when someone cracks a knuckle by pulling or bending the finger joint, and why can't you crack the same knuckle again right away?
Can a closed loop of buoyant floats, rigged to pass continuously up through a column of water and back down outside it, be made to turn forever and deliver free work, since Archimedes' principle gives every submerged float an upward buoyant force?
Why trees cannot grow taller than about 130 meters
Research level
What physical limit stops trees from growing indefinitely taller, and what is the actual maximum height set by water transport physics?
Splash crown formation from a falling drop
Research level
When a drop or stone hits a liquid surface fast enough, why does the splash form a crown of regularly-spaced spikes, and how does the crown height depend on impact speed and drop size?
Can a person or animal run on the surface of water?
Research level
Why can basilisk lizards run across open water without sinking, and could a human do the same thing at ordinary Earth gravity?
Given a snow-covered mountain slope of a certain height and angle, roughly how fast will an avalanche be moving by the time it reaches the bottom, and how far will the debris travel?
When a tiny gas bubble trapped in water is driven to violently collapse by a sound wave, why does it emit a flash of light -- and why is the exact mechanism that produces that light still debated among physicists?