Author(s): R. Lopes; J. Matos; J. F. Melo
Linked Author(s):
Keywords: Labyrinth weir; Crest coefficient; Free-flow; Submergence
Abstract: This paper presents a comparative study on crest coefficients for trapezoidal labyrinth weirs with distinct crest shape, based on data available in the literature along with new experimental data obtained in a facility assembled at the National Laboratory of Civil Engineering. The results indicate that, for free-flow conditions, the relative differences are generally lower than 10%, except for very small total upstream head, or for moderate to large total upstream head, in the situation where the nappe was not fully aerated. The labyrinth weir dimensionless submerged head presented herein is also compared with the formula developed by Tullis et al. (2007), based on data gathered on labyrinth weirs with half-round crest shape and various sidewall angles. The present results are within 6% of those predicted by the above mentioned formula, suggesting that the influence of labyrinth crest shape and sidewall angle on the dimensionless submerged weir head is small, within the range of tested conditions.
Year: 2009