1,720,968 research outputs found
Discussion on “Computing the Trajectory of Free Jets” by T.L. Wahl, K.H. Frizzell and E.A. Cohen
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Nappe flow over horizontal stepped chutes
No full textStepped chutes have been frequently used since the 1980s in order to take advantage of their dissipation efficiency, aeration characteristics and relative ease of construction. Two basic flow regimes exist for stepped chutes: nappe flow and skimming flow, with the nappe flow having received less attention in comparison to the skimming flow regime. This work suggests a simple iterative method, valid for sub-to-supercritical approach flow conditions, for predicting the basic nappe flow features on a horizontal multi-step structure. The proposed calculation procedure, if applied along the stepped chute, allows us to calculate the flow depth at each step brink and at each nappe impact point, the thickness of the water cushion beneath the nappe, the jet impact length and the energy dissipation rate. For validating the proposed analytical approach, a comparison between experimental and calculated data is also presented
Modelli di simulazione di sistemi di approviggionamento idrico per la definizione di politiche di gestione della domanda
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Experimental study on a plane free overfall
No full textThis paper deals with the analysis of collected experimental data on free overfall in sub-critical and super-critical flow conditions, using the analytical and empirical approaches available by the technical literature. The aim is to provide new informations and tools useful to design correctly a single drop hydraulic structure
Air-water flow features in skimming flow over steeply sloping stepped spillways
No full textSkimming flow over a stepped spillway is characterized by strong self-aeration downstream of the point of inception of air entrainment. In order to have a better understanding of the overall phenomenon of air entrainment and flow bulking, the main features of the self-aerated flow need to be evaluated. An experimental study has been carried out in a large-scale stepped chute assembled at the National Laboratory of Civil, Lisbon, in order to collect new air concentration data in skimming flows. In the present paper it is shown that some existing analytical models for predicting the air concentration distribution, as well as the development of the mean air concentration down the chute, compare fairly well with the experimental dat
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