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Old   October 11, 2010, 00:05
Smile interesting question in fluid mechanics
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Consider a person is walking first in air and then in water at same speed. For which motion will be the Re be higher and why?
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Old   October 11, 2010, 00:44
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Considering the person as an sphere falling in a fluid, Re=v*D/nu, so Re will be greater in air.

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Old   October 11, 2010, 02:26
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nu(kinematic viscosity) for water is smaller than air at room temperature.
So Re is higher for when person moves in water.
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Old   October 11, 2010, 11:29
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Aha, it is around twenty times greater, rho did the trick.

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