a smooth 10 cm diameter sphere is immersed in a stream of 20 degree celcius water moving at 5 m/s. The appropriate Reynolds number of this sphere is ...?

 a smooth 10 cm diameter sphere is immersed in a stream of 20 degree celcius water moving at 5 m/s. The appropriate Reynolds number of this sphere is  ...?

 

diameter of sphere, D = 10 cm = 0.1 m 

 

speed of sphere , v = 5 m/s

 

 

now, we know that 

 

dynamic viscosity of water , μ = 0.001 Kg/m.s

 

 

density of water,                    ρ = 998 kg/m^3  at 20 degree celcius

so, Reynolds  Number , Re = `\frac{ρ\v\D}{μ\}`  

 

                                       Re = `\frac{998\times 5\times 0.1}{0.001\:}`=  499000  Answer