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GATE 2018 CE (CE2) – Question 23

Hydraulics · Channel hydraulics: specific energy, critical flow, uniform flow, hydraulic jump · 1 mark · Multiple choice

For fixed open-channel discharge, the two depths with equal specific energy are called ______.

  1. alternate depths
  2. critical depths
  3. normal depths
  4. sequent depths

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Show answer and explanation

Correct answer: (A) alternate depths

Explanation

At fixed discharge, a specific-energy curve above its minimum has one shallow supercritical depth and one deeper subcritical depth. They are **alternate depths, A**. Sequent or conjugate depths instead share the momentum function across a hydraulic jump and generally have different specific energies.