Discuss the limitations of the 1/7th power law u/u-(y/R) for the velocity profile in a circular pipe of radius R, indicating the range of Reynolds numbers for which this law is applicable. (b) Show that the mean velocity is given by 49u1/60. (c) Water flows at a volumetric flow rate of 1.1 x 10-3 m3/s in a tube of diameter 25 mm. Calculate the centre-line velocity and the distance from the wall at which the velocity is equal to the mean velocity. -0.25 (d) Assuming that Cf-0.079(Re) laminar sub-layer thickness. evaluate the wall shear stress and hence estimate the = 0.89 x 10-3 N s/m2. p = 998 kg/m.