The present research was conducted to investigate the effect of sill geometry and sill width on the discharge coefficient and hydraulic jump characteristics. For this purpose, sills with semi-cylindrical, cylindrical, pyramidal, and rectangular cube geometries with widths of 0.075, 0.10, 0.15, and 0.2 m were installed under a sluice gate. Results showed that increasing the sill width increased the sluice gate discharge coefficient compared to the no-sill mode. The results of placing a sill with different geometric shapes under a sluice gate indicate that using a semi-cylindrical sill increases the discharge coefficient. The ranked order of other sills, from the largest to smallest discharge coefficient, is: cylindrical, pyramidal, and rectangular cubic sills, respectively. The results show that the use of a sill increases the energy dissipation. Examining sills of different widths indicates that with increasing width, the increase in velocity and consequent decrease in the depth of the hydraulic jump causes an increase in energy loss. When employing sills of maximum width (b = 0.20 m) for pyramidal, semi-cylindrical, cylindrical, and rectangular shapes, the energy loss increased by 125, 119, 116, and 125% in section A, respectively. The semi-cylindrical sill is most effective in increasing the discharge coefficient, while the pyramidal sill is most effective for increasing energy dissipation.

This paper aims to explore the effects of a sill under a standard sluice gate on the development of the intake vortices. In total, 200 experiments were carried out. Sills with different shapes and widths were considered both numerically and experimentally. Results indicated that using a sill changes the flow depth and upstream pressure. Using a silled gate causes a decrease in the amount of air entering the fluid. By increasing the sill width, the vortex intensity reduces and this reduction is further amplified by increasing the approach discharge. The experimental findings are also compared to the results from the numerical model Flow-3D with interesting agreements.

Sediment transportation on coasts can be significantly affected by rivers, wave–wind effects, and human activities. As a result, undesirable effects such as shoaling or erosion may occur in fishery shelters. This study examines the “Sandıktaş a Fishery Shelter”, a coastal structure in the Eastern Black Sea region of Turkey, and its susceptibility to shoaling. Bathymetric measurements were performed within the nearshore and onshore, and sediment samples were taken periodically from selected points and analyzed in the laboratory. The characteristic grain diameters of the sedimentation were obtained. It was revealed that the average grain diameter was d₅₀ = 0.30–0.91, caused by an increase of 11,611 m³ in shoaling, which caused the decrease of 8 cm water depth that occurred between 2019 and 2022. The entrance of the fishery shelter has become progressively shallower, making it difficult for boats to navigate. Existing breakwater configurations played a role in trapping sediments, requiring optimized breakwater designs/modifications for improved sediment control. The Mann–Kendall test showed an increasing trend in sediment accumulation, particularly in coarser fractions. The findings highlight the necessity of periodic dredging and potential structural modifications to mitigate shoaling and ensure the long-term sustainability of the fishery shelter. Moreover, they emphasize the critical challenges caused by sedimentation in fishery shelters and provide data-driven recommendations for enhancing coastal engineering practices and maintenance strategies.

This study examines scour development downstream of hydraulic structures, focusing on screen plates as a mitigation measure. To function as energy dissipators, screen plates with varying aperture ratios were strategically placed at a specified distance from the sluice gate. In particular, the maximum and minimum depths and lengths of scour holes were observed for screens with aperture ratios of 40 and 50%, respectively. A moving bed with particles of different sizes was then selected. Results show that maximum scour depths ranged from 8 to 23 cm, while scour lengths varied between 30 and 85 cm, with finer sediments producing deeper and longer scour holes. Increasing the screen aperture ratio and thickness generally reduced scour intensity, and optimally positioned screens enhanced energy dissipation, decreasing sediment transport by up to 40 %. Consequently, increasing the aperture ratio and the thickness of the screens correlates with a decrease in scour hole size, suggesting, e.g., potential strategies to improve the bridge's resistance to scour. These findings provide valuable insights for the design and optimization of scour protection measures, offering practical guidance for enhancing the stability and longevity of hydraulic structures in real-world applications.