New Relationship between a Vertical Gate Opening and Downstream Flow Stability: Experimental Development

Vertical gates are important hydraulic structures that control the regime and characteristics for both downstream and upstream flows of streams and canals. In this study, laboratory tests were conducted to find a relationship between gate opening, as function of upstream water depth, and downstream flow conditions. The study was conducted in a laboratory flume, within a range of fourteen (14) discharges, seeking to identify an optimum vertical gate opening at which flow stability occurs; fuzzy theory concepts were used to define “stability.” Ten (10) of the tested discharges were used as calibration data and four (4) were used in validation. A regression model, based on fundamental dimensionless parameters, was developed, and is, herein presented, which links optimum gate opening as function of upper water depth and critical discharge. The model offers a validated (i.e., within the scope of the experiments) new relationship that can be used to best operate vertical gates ensuring stable flow characteristics.