Drilling fluid is pumped down through the center pipe of a well and then rises up within the annulus. Determine the velocity of the fluid forced out of the well as a function of the diameter d of the...

Drilling fluid is pumped down through the center pipe of a well and then rises up within the annulus. Determine the velocity of the fluid forced out of the well as a function of the diameter d of the inner pipe, if the velocity of the fluid forced into the well is maintained at V_in
= 2 m/s. Neglect the thickness of the pipes. Plot this velocity (vertical axis) versus the diameter for 50 mm
 d
 150 mm. Give values for increments of ∆d = 25 mm.