A hydraulic jump ensures?

LMRC AM 2015

⭕ (a) Change of subcritical flow to super-critical flow

⭕ (b) Change of supercritical flow to sub-critical flow

⭕ (c) Change of subcritical flow to critical flow

⭕ (d) Change of supercritical flow to critical flow

Explanation: A hydraulic jump is a phenomenon observed in open channel flow when the flow transitions from supercritical to subcritical state. This abrupt transition results in a sudden rise in water surface and is typically accompanied by intense turbulence and energy dissipation in the form of turbulent rollers.

Hydraulic Jump in Open Channel Flow

A hydraulic jump occurs when a supercritical flow (fast and shallow) is suddenly slowed, resulting in a subcritical flow (slow and deep). This phenomenon is common in spillways, canals, and downstream of sluice gates.

Key Characteristics:

• Occurs when high-velocity flow transitions into low-velocity flow.
• Results in a sudden increase in water depth.
• Causes significant energy dissipation and turbulence.
• Used for energy dissipation in hydraulic structures.

Conclusion:

The correct answer is Change of supercritical flow to sub-critical flow. Hydraulic jumps play a vital role in fluid mechanics and are important for designing safe water conveyance systems.

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