Author(s): K. Babaeyan-Koopaei; E. M. Valentine; D. Alan Ervine
Linked Author(s):
Keywords: Ir-regulated flow; Siphon spillway; Reservoir; Airation; Two phase flow; Air entrainment
Abstract: A physical hydraulic model study has been conducted to investigate the hydraulic characteristics of the siphons on the Brent Reservoir spillway in order to establish reliable stage discharge relationships. The existing bellmouth siphon system is unsuitable causing the siphons to prime suddenly at discharges around 3m3/s. This is due to the sudden removal of an air pocket from the siphon crown. The model tests were carried out in two stages. In the first stage, the existing geometry is examined. The reservoir levels for priming of each of the existing siphon configurations were established. Based on the results from stage 1 of the experiments, it was concluded that the air inlet requires redesign and various options to improve the air regulation should be considered. In the second stage, various options to regulate air inlet and establish a stable siphon perfomance over the entire range of discharges were considered. It was found that the most stable conditions are provided by a slot being cut in the spillway hood at an appropriate level. This geometry provides excellent air-regulated stability, unimpaired spillway capacity, and is insensitive to tail water level and wave conditions in the reservoir.
Year: 2001