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?

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

Regards.

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

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

Regards.