Effects of Geometrical Parameters on Labyrinth Weir Hydraulics

Abstract

The effects of geometrical parameters (crest height, number of cycles, and plan weir configuration), are investigated experimentally on labyrinth weirs, over a range of headwater ratios of 0.1 to 0.6. Trapezoidal and triangular weirs have a constant angle α=15°, whereas rectangular weirs have the same footprint size B as the trapezoidal configuration. Data uncertainties are quantified at a relatively small overall average of 1.88%. For taller labyrinth weirs, current experimental models achieve lower discharge coefficients when all other geometrical parameters are kept the same. Increasing the number of cycles also leads to a reduction in flow rate and discharge coefficient. These hydraulic performance reductions were most significant for trapezoidal followed by rectangular and triangular configurations. For the same geometrical conditions, a rectangular configuration had a higher flow rate for each head, followed by trapezoidal and then triangular. Nappe behaviors were significantly different between the configurations, whereas modifying the geometrical ratios had less significant effects on the flow characteristics of each configuration.