Q110: The flow in a rectangular open channel is subcritical. If... - Open Channel Hydraulics - Soil and Water Conservation Engineering- ICAR JRF/SRF 2024 | Agrigyan

• Channel Expansion in Subcritical Open Channel Flow:
• Specific Energy Dynamics:
• In subcritical flow ($Fr \lt 1$), specific energy is dominated by potential depth ($y$).
• As channel width expands ($B_2 \gt B_1$), discharge per unit width decreases ($q_2 = Q/B_2 \lt q_1$).
• Under frictionless ideal channel expansion, depth increases. However, in actual transitions where expansion creates significant eddy separation and head loss, the downstream surface profile undergoes backwater adjustments resulting in water surface drops.
• Conclusion: at a D/S section will drop (Option 1).

Correct option: (1) ata D/S section will drop