Author(s): Koroungamba Laishram; Thiyam Tamphasana Devi; Ngangbam Romeji Singh; Potsangbam Albino Kumar

Linked Author(s): Ngangbam Romeji Singh

Keywords: CFD; Open channel flow; Hydraulic jumps; Bed roughness; Sloping channel; Energy dissipation

Abstract: Hydraulic jumps are used as an energy dissipater, allowing excess energy from downstream flow to be dissipated through hydraulic structures, preventing scouring. Channel roughness is also necessary for good flow control, as it allows more excess energy to be dissipated downstream. To better understand the impact of channel roughness on dissipating energy in an open channel, this study investigates and compares the energy dissipation of hydraulic jumps based on roughened (gravel size 20mm) horizontal and sloping channel bed condition. The experiment was carried out in the Hydraulics Laboratory, Department of Civil Engineering, NIT Manipur (India) in a rectangular channel flume (16 m length, 0.6 m wide, and 0.8 m deep). The characteristics of hydraulic jumps (length of jump, upstream and downstream head, velocities, and subsequent depth ratio) were measured and using these characteristics, the amounts of energy dissipation are calculated. Results show that the sloping channel bed is much safer for the structure, dissipates more energy, and the control of the flow is much easier as compared to the horizontal condition. Thus, it can be suggested that sloping channel bed is an effective channel bed condition when energy dissipation is the main purpose. The experimental results were numerically simulated using CFD (Computational Fluid Dynamics) techniques and found to be within an acceptable range.

DOI: https://doi.org/10.26077/cb4c-fdc3

Year: 2022