The pressure drop across a length L of the pipe is

Question

The velocity profile in fully developed laminar flow in a pipe of diameter D is given by u = u₀(1 – 4r² / D²), where r is the radial distance from the centre. If the viscosity of the fluid is m, the pressure drop across a length L of the pipe is                                                 

      (a) $\frac{\mu \mu _{0}}{D_{2}}$                                                               (b) $\frac{4\mu \mu _{0}}{D_{2}}$ 

      (c)$\frac{8\mu \mu _{0}}{D_{2}}$                                                            (d)$\frac{16\mu \mu _{0}}{D_{2}}$