EXPERIMENTAL STUDY OF DAM BREAK FLOW GENERATED BY THE FLAP GATE IN HORIZONTAL CHANNEL

The risk of dam break failure become one of the most important issues to decide the feasibility of reservoir and dam development in Indonesia. This paper presents an experimental work result of a dam break flow through a single oblique obstruction in a straight rectangular channel. The dam break flow was generated by a sudden swing of a flap gate set on the contraction join of a horizontal reservoir and a horizontal channel. The initial condition of the dam break flow is set up based on the water height in this reservoir. A spatial temporal measurement of depth and velocity of the generated dam-break flow was conducted around the obstruction. The flow depth was measured using an ultrasonic-based sensor supported by a GPRS communication system, and the flow velocity was measured using a high-speed type current meter. Less correlation between the measured depth and velocity flow in the first of three seconds after the flow generation, where the flow has a high intensity of turbulent, was observed due to the limitation of data acquisition capacity. Compared to Noel's experimental works where the dam-break mechanism is simulated using an uplift gate, the flow depth and velocity profiles of the current experimental work have a good agreement in its pattern and in less agreement in its magnitude. Meanwhile, compared to Noel's numerical model result, it has fewer agreement results. These differences might be occurred due to the influences of differences dam break mechanism and data acquisition system.