Author(s): K. S. Vikas; A. Sarkar

Linked Author(s):

Keywords: Sharp-crested weir; Submergence; Flow regimes; Free Surface

Abstract: The higher water levels unanticipated at the time of floods are not generally considered in the design of hydraulic structures. The present study emphasizes the experimental investigation for the characterization of submerged flow regimes downstream of a rectangular sharp-crested weir at three different slopes (0, 0.004, and 0.008) that are possible with a laboratory flume. The classical flow patterns of submerged regimes, namely impinging jet, surface wave, surface jump, and surface jet regime, were analyzed. The experiments were conducted to examine the water profiles and the variations of different parameters, representing surface jumps and surface waves, with a gradual rise in submergence. The range of t/h values (where t and h are the downstream and upstream depths above the crest of the weir) at which these regimes shift from one to another were observed to vary with the slope. The photographs of the patterns of the submerged flow regimes at three different slopes and six variants of discharge were captured, and image analysis was carried out. The profiles were extracted for each submergence level to develop the correlations for various characteristics of surface jumps and waves. With an increase in the submergence, the non-dimensional lengths of the surface jumps decreased at all the slopes and were within a range of 10 to 55, whereas the non-dimensional heights increased and were within a range of 0 to 0.7. The surface wave with a maximum normalized amplitude of 0.6 and a maximum normalized wavelength of 4 faded out gradually as the regime ends.

DOI: https://doi.org/10.26077/010f-f6ea

Year: 2022