Hydraulics of Plane Plunge Pool Scour |
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Authors: | Stefano Pagliara Willi H. Hager Hans-Erwin Minor |
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Affiliation: | 1Professor, Dip. di Ingegneria Civile, Univ. di Pisa, Via Gabba 22, I-56 100 Pisa, Italy. 2Professor, VAW, ETH Zürich, CH-8092 Zurich, Switzerland.
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Abstract: | Plunge pool scour involves a significant risk with trajectory spillways because of structural undermining at a dam foot or destabilization of adjacent valley slopes. An experimental program towards the understanding of plane plunge pool scour of a completely disintegrated rock surface was conducted, in which the following items received attention: jet shape, jet velocity, jet air content, tailwater elevation, granulometry, upstream flow to the scour hole, and the end scour profile in terms of the basic scour features. These effects were experimentally investigated based on a systematic variation of the governing scour parameters. The results of this paper allow answering questions that have so far not been addressed. Design equations were proposed to sketch the main tendency of the data sets. The significant effect of the densimetric particle Froude number was substantiated. This research may be used to estimate the prominent scour features for nearly two-dimensional jet arrangements involving a pre-aerated high-speed flow. |
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Keywords: | Air water interactions Hydraulic structures Scour Spillways Pools |
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