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Comment on How would I go about turning this into a power-generating wind turbine.

litchralee@sh.itjust.works ⁨16⁩ ⁨hours⁩ ago

I agree that RPM isn’t the primary quality to assess here, but I think angular momentum doesn’t really matter either. As a quantity, momentum describes a conserved capacity to store kinetic energy. As in, it could tell us how long the fan would stay in motion when the wind stops blowing. But that’s not the objective for a wind turbine, which is supposed to draw energy from the wind to do some work.

Also, I understand angular frequency (the magnitude component of angular velocity, which would also have a phase angle) customarily uses rad/sec but is directly convertible to RPM. Which as we agree, is not the primary quantity for a windmill.

At bottom, none of these quantities are the useful metric for what makes a good wind turbine. And that’s expected, because we have few details about the fan itself: the blade pitch, stall speed, and fan diameter. The only firm detail we can see is the blade count from the picture.

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scarabic@lemmy.world ⁨4⁩ ⁨hours⁩ ago
I believe you’re thinking of momentum in a narrow sense: the energy an already-moving object has that allows it to move for a while before stopping. And it was meant in a more general sense ie the amount of energy being generated and doing work.

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TheTechnician27@lemmy.world ⁨15⁩ ⁨hours⁩ ago
N… No? The wind applies a torque to the wind turbine that gets converted into angular momentum. The angular momentum drives a generator that produces electricity. The obvious point I was making was that the electricity produced doesn’t rely just on ω but also the moment of inertia I.

I feel like I’m being gaslit right now. Like: “Momentum doesn’t really matter in assessing how deadly a collision with this car would be. I feel like that’s expected because we have few details about the car itself.” ???

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