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student October 11, 2010 00:05

interesting question in fluid mechanics
 
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?
please post your answers?

santiagomarquezd October 11, 2010 00:44

Considering the person as an sphere falling in a fluid, Re=v*D/nu, so Re will be greater in air.

Regards.

student October 11, 2010 02:26

nu(kinematic viscosity) for water is smaller than air at room temperature.
So Re is higher for when person moves in water.

santiagomarquezd October 11, 2010 11:29

Aha, it is around twenty times greater, rho did the trick.

Regards.


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