Effect of Perforated Sills on Maximum Scour Depth Downstream From a Sluice Gate

Experiments were conducted to study the effect of using a perforated sill on maximum scour depth downstream from a sluice gate.

Previous studies have shown that screens may be utilized efficiently for dissipating the energy of water downstream of a hydraulic structure.

For the present study, a series of experiments was conducted to investigate the effect of using a perforated screen sill on the maximum scour depth downstream of a hydraulic structure.

In the present study, a single perforated sill with varying porosity (10.3%, 18.3%, 28.5%, and 41.1%) and an inclination angle of 90° were used. Perforated sill with different shapes of holes (circular, rectangular, and square holes) was used during the study. The major parameters for the present study are the porosity of the perforated sill, different shapes of holes, downstream water depth, and the Gate Froude number (F_G) for a range covering from 2.15 to 4.7. The gate opening simulating a hydraulic structure is adjusted at heights of 4 cm, 5 cm, and 6 cm during the experiments work.

The results revealed that an increase in the sill porosity (Ao/As) increases the screen effect to reduce the max scour depth. In addition, the results showed that the sill with square holes is better than the sill with circular and rectangular holes in reducing the maximum scour depth.

The perforated sill with a square porosity of 41.1% reduces the maximum scour depth downstream of a sluice gate by 60%.