Elevated Crests and Their Impact on Flow Dynamics in Crump Weir Structures

This study examines the hydraulic performance of three crump weir configurations with varying crest heights, focusing on flow characteristics, energy dissipation, and pressure distribution under different conditions. The discharge curves indicate that crest height significantly influences flow sensitivity and energy distribution. While the highest crest (CW-3) enhances flow sensitivity and upstream stability, lower crests improve energy dissipation and reduce residual energy at varying velocities. CW-1 offers a balanced performance for moderate flows by retaining sufficient energy while effectively dissipating excess. Free surface flow analysis reveals that higher crests promote uniform flow and reduce turbulence, especially at high velocities, and elevate upstream water levels for improved stability. However, greater crest heights do not consistently lead to higher energy dissipation. CW-2, with its intermediate height, achieves the best balance between energy dissipation and flow control, indicating optimal hydraulic efficiency. Pressure analysis shows that while CW-3 increases upstream pressure and flow regulation, shorter weirs can occasionally create higher local pressures downstream due to turbulence. Overall, a medium crest height provides the most efficient energy dissipation by balancing residual energy with hydraulic performance.