Magnetohydrodynamics - Propelling Liquid Metal with Magnets!
Why Hacker News recommends it
It comes up as a great explainer on magnetohydrodynamic drives and pumps in threads about silent submarine propulsion.
What it is
Tech Ingredients explains the principles of magnetohydrodynamics and builds several demonstrations, including propelling liquid metal and electrolytes with magnets and a railgun-style setup.
Recommended by 2 HN commenters across 2 different months, 2018 to 2023.
What Hacker News said
Strong rec bloudermilk · 2020-01 · on “The propeller is giving way to the pump-jet propulsor on larger submarines”
There's a great video from one of my favorite YouTube channels about Magnetohydrodynamic drives. Really fascinating drive design and channel for anyone interested in engineering. [this video]
Recommends elihu · 2023-06 · on “Taking a New Look at Fundamental Tech for Quiet Undersea Propulsion”
Interesting. If I understand correctly, they need a electrode that's in physical contact with the sea water. I'm not sure I understand it entirely, but there's a video on the Tech Ingredients channel that explains magnetohydrodynamic pumps: [this video]
Cites macromaniac · 2018-09 · on “Magnetic Field Record Set with a Bang: 1,200 Tesla”
If can get to 4 billion tesla I /think/ that's enough to generate electrons from the vacuum of space (see:schwinger magnetic induction) and you could do something akin to magnetohydrodynamics ( see: [this video] ) which would use the magnetic field to accelerate the electrons away from the ship, I could be incorrect here though