An Enhanced Physically Based Scour Model for Considering Jet Air EntrainmentReport as inadecuate




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Published in: Engineering, vol. 3, num. 2, p. 294-301 Amsterdam: Elsevier Science Bv, 2016

Based on systematic experiments on the influence of air entrainment on rock block stability in plunge pools impacted by high-velocity jets, this study presents adaptations of a physically based scour model. The modifications regarding jet aeration are implemented in the Comprehensive Scour Model (CSM), allowing it to reproduce the physical-mechanical processes involved in scour formation conceming the three phases; namely, water, rock, and air. The enhanced method considers the reduction of momentum of an aerated jet as well as the decrease of energy dissipation in the jet diffusive shear layer, both result-ing from the entrainment of air bubbles. Block ejection from the rock mass depends on a combination of the aerated time-averaged pressure coefficient and the modified maximum dynamic impulsion coef-ficient, which was found to be a constant value of 0.2 for high-velocity jets in deep pools. The modified model is applied to the case of the observed scour hole at the I<ariba Dam, with good agreement.

Keywords: Air entrainment ; Uplift ; Rock scour ; Dam safety ; High-velocity jets ; Block satbility ; Scour assessment Note: [1109] Reference EPFL-ARTICLE-222953doi:10.1016/J.Eng.2016.03.003View record in Web of Science





Author: Duarte, Rafael; Pinheiro, António; Schleiss, Anton

Source: https://infoscience.epfl.ch/record/222953?ln=en







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