Chapter 7, Problem 133P

A one-third scale model of an airplane is to be tested in water. The airplane has a velocity of 900 km Ii in air at -50°C. The water temperature iii the test section is 10°C.
The properties of air at 1 atm and -50°C: $\rho =1.582{\text{kg/m}}^3$ , $\mu =1.474\times {10}^{-5}$ kg/m.s.
The plopelties of water at 1 atm and 10°C: $\rho =999.7{\text{kg/m}}^3$ , $\mu =1.307\times {10}^{-3}\text{kg/m}\cdot \text{s}$ .
In order to achieve similarity between the model and the prototype, the water velocity on the model should be
(a) 97 km/h
(b) 186 km/h
(c) 263 km/h
(d) 379 km/h
(e) 450 km/h