Basic Fluid Mechanics

To simulate the aerodynamic forces on a cylinder of 1 m diameter due to a uniform air flow of 1 m/s at standard temperature and pressure (STP), a scale model of 10 cm diameter is tested in a water tunnel at standard conditions. The required water flow velocity (in m/s) in the water tunnel for Reynolds number similarity is _________ (round off to the nearest integer). (Take $\nu_{air} = 1.5 \times 10^{-5}$ m$^2$/s and $\nu_{water} = 1.0 \times 10^{-6}$ m$^2$/s)