Project ForgeSign up free
Fluid Mechanics
Flow Through Pipes
GATE 2009
Medium

Two identical reservoirs, open at the top, are drained through pipes attached to the bottom, of the same length but different diameters (D1>D2). Assuming steady, laminar flow in both drain pipes, if the volumetric flow rate in the larger pipe is 16 times that in the smaller pipe, the ratio D1/D2 is

  • 2
  • B4
  • C8
  • D16

Explanation

For laminar flow with the same driving head, length, and fluid: Q∝D⁴. Q1/Q2=16=(D1/D2)⁴ ⟹ D1/D2=16^0.25=2.

Source: GATE CH 2009 (2009)

This question is part of a 15-day revision cycle — sign in and Project Forge will bring it back the day before you'd forget it.

Start revising free