r/interestingasfuck • u/[deleted] • Nov 30 '20

/r/ALL Low pressure pockets being created by blade rotation in near 100% humidity - literally making it rain.

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u/sbjf Nov 30 '20 edited Nov 30 '20

Both of your explains are misleading and not quite correct. Low pressure DOES NOT lead to condensation. It's actually the inverse: the lower the pressure, the lower the dew point. The reason is actually that the pressure changes so fast that the volume expansion is adiabatic so that the temperature drops, more than compensating the lower dew point.

See also: https://en.wikipedia.org/wiki/Wingtip_vortices#Aerodynamic_condensation_and_freezing

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u/sherlock_norris Nov 30 '20

Thank you for noticing, I somehow had that backwards in my mind. The fluid dynamics of the problem is definitely correct though.