Also, they only considered gates operating at least partly drowned, whereas an ERS often operates in a completely free-flowing condition. For these reasons a new experimental investigation was undertaken that encompassed drowned and undrowned flow with a range of pipe slopes, lengths and shapes and different gate masses. A dimensional analysis was undertaken that identified the key parameters in the experimental work. Physical arguments were given to suggest a form of the functional relationship between the parameters. Analysis of the test results showed that the form of the functional relationships was correct and that simple equations could be used to calculate the flowrate from the measured head.
Further testing is required to fully quantify the influence of the gate rest angle.