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Cake day: November 19th, 2023

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  • When wind speed doubles, the energy it carries increases eightfold,

    Edit: I’m wrong, see edit below!

    Huh? Kinetic energy increase is square, not cubic.

    KE=1/2 m v^2

    So every doubling of speed should increase the available kinetic energy by 4 times, not 8. 3 times the speed is 9 times the energy. Granted there are probably some efficiency gains in excess of this at the low end, but as a rule that’s just wrong.

    Edit: Cool, I learned something new! I neglected to consider it in terms of power, just thought about kinetic energy.

    So something like: KE = 1/2 m v^2

    = 1/2 ( rho V) v^2

    = 1/2 ( rho A d) (d/t)^2

    = 1/2 rho A d^3 1/t^2

    Where P = KE/t

    Thus:

    P = 1/2 rho A (d/t)^3

    = 1/2 rho A v^3

    Lots of other aspects I’m sure I have wrong, but I see how the cubic came to be.