Fluid Mechanics seventh edition by Frank M. White · Problem P6.16
Viscous Flow in Ducts — Frank M. White
Physics — Fluid Mechanics · laminar-pipe-flow
Problem
Fluid flows steadily, at volume rate Q, through a large pipe and then divides into two small pipes, the larger of which has an inside diameter of 25 mm and carries three times the flow of the smaller pipe. Both small pipes have the same length and pressure drop. If all flows are laminar, estimate the diameter of the smaller pipe.