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cma 2 days ago [-]
It would have been awesome if this was what helped craft the navier stokes blow up. The maximizing shrimp welfare wing of the rationalists/EAs might have had been put into a crisis though. Study the shrimp in lab conditions to only need weaker AI to solve our hardest problems, or maximize their happiness with the whole sea monkey catalog of accessories?
peter_d_sherman 24 hours ago [-]
>"In such a system, energy moves between size scales. English mathematician and physicist Lewis Fry Richardson, the founder of modern weather forecasting, discovered this when he studied the fluid systems formed by gases in the atmosphere. He found that the kinetic energy of a large eddy feeds into smaller and smaller eddies, until it reaches the scale where viscosity, which resists motion, takes over. The energy is ultimately dissipated as heat. In 1922, Richardson captured the concept in verse:
Big whorls have little whorls
Which feed on their velocity,
And little whorls have lesser whorls
And so on to viscosity.
[...]
Si and Fang ran the brine shrimp experiment repeatedly. They found that when a solo shrimp swam at an angle of less than 45 degrees to the direction of maximum stretching, the energy flowed from smaller scales to larger ones, feeding the flow itself, as they’d predicted for a 2D system. But if the shrimp swam at an angle of more than 45 degrees to the direction of maximum stretching, the energy went in reverse, pulling from the larger scale of the flow to energize smaller perturbations.
[...]
It was interesting because they were saying that with small, specific interventions in the flow we can … show a transfer of energy between scales,” De Serio said. They demonstrated that with minimal manipulation, the energy flux in a 2D system can be steered to act more like (but not exactly like) the flux in a 3D one, which suggests that physicists might be able to apply insights from one dimensional domain to the other."
Big whorls have little whorls
Which feed on their velocity,
And little whorls have lesser whorls
And so on to viscosity.
[...]
Si and Fang ran the brine shrimp experiment repeatedly. They found that when a solo shrimp swam at an angle of less than 45 degrees to the direction of maximum stretching, the energy flowed from smaller scales to larger ones, feeding the flow itself, as they’d predicted for a 2D system. But if the shrimp swam at an angle of more than 45 degrees to the direction of maximum stretching, the energy went in reverse, pulling from the larger scale of the flow to energize smaller perturbations.
[...]
It was interesting because they were saying that with small, specific interventions in the flow we can … show a transfer of energy between scales,” De Serio said. They demonstrated that with minimal manipulation, the energy flux in a 2D system can be steered to act more like (but not exactly like) the flux in a 3D one, which suggests that physicists might be able to apply insights from one dimensional domain to the other."
Absolutely fascinating! Great article!
Potentially related:
https://en.wikipedia.org/wiki/Angular_momentum
https://en.wikipedia.org/wiki/Noether%27s_theorem