• discharge coefficient
• Piano Key Weirs
• PKW

The continuing need for dam safety suggest that some spillways are undersized and they need to improve their discharge capacity and their stability. Piano Key Weirs are a suitable solution due to a good technico-economical optimization.

Piano Key Weirs are non linear hydraulic structures with an higher discharge capacity compared to regular weirs, especially for low heads. In the past twenty years, many experiments have been conduced to identify the geometrical parameters for an hydraulic and economical optimization. First this work describes the main geometrical parameters that characterize the structure, to understand how this parameters influence the discharge capacity. Next an entire chapter is dedicated to the calibration of the utilized sensors to collect data. Since the present study highlighted that, to collect data, is possible to use not only ultrasonic sensors, but even pressure probes with a submerged set up. Later on the PKW applications are described, focusing on the calculation of the discharge capacity with the two different tools and with different experimental set up. In fact the ultrasonic sensors have been installed at different positions from the weir. Instead the pressure probes, due to their complicated installation, they have never been moved from the initial position. In the final part of this work is possible to find the result analysis. This part describes the flow depth, the discharge coefficient and the scale effects for all the different positions.