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GATE 2026 ME – Question 24

Fluid Mechanics · Flow through pipes, head losses, bends and fittings · 1 mark · Multiple choice

A steady incompressible laminar flow passes through a 90° tube bend placed on a horizontal surface. In horizontal diametric plane, two pressure taps $P_i$ and $P_o$ are provided across the cross-section at inner and outer walls of the bend, respectively. Which one of the following options is correct?

  1. $P_o > P_i$
  2. $P_o < P_i$
  3. $(P_o - P_i)$ is directly proportional to the bend radius.
  4. $(P_i - P_o)$ is inversely proportional to the average flow velocity.

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Show answer and explanation

Correct answer: (A) $P_o > P_i$

Explanation

As the fluid goes around the bend, the pressure gradient across the cross-section must supply the centripetal force that turns the fluid. So the pressure rises from the inner wall to the outer wall, which means $P_o > P_i$.