Characteristics of submerged jets in evolving scour hole downstream of an apron

Dey, Subhasish ; Sarkar, Arindam (2008) Characteristics of submerged jets in evolving scour hole downstream of an apron Journal of Engineering Mechanics, 134 (11). pp. 927-936. ISSN 0733-9399

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Official URL: http://ascelibrary.org/emo/resource/1/jenmdt/v134/...

Related URL: http://dx.doi.org/10.1061/(ASCE)0733-9399

Abstract

This paper reports an experimental investigation on the velocity and turbulence characteristics in an evolving scour hole downstream of an apron due to submerged jets issuing from a sluice opening detected by an acoustic Doppler velocimeter. Experiments were carried out for the conditions of submerged jets, having submergence factors from 0.96 to 1.85 and jet Froude numbers from 2.58 to 4.87, over sediment beds downstream of a rigid apron. The distributions of time-averaged velocity vectors, turbulence intensities, and Reynolds stress at different streamwise distances are plotted for the conditions of initial flat bed, intermediate scour holes, and equilibrium scour hole downstream of an apron. Vector plots of the flow field show that the rate of decay of the submerged jet velocity increases with an increase in scour hole dimension. The bed-shear stresses are determined from the Reynolds stress distributions. The flow characteristics in evolving scour holes are analyzed in the context of self-preservation, growth of the length scale, and decay of the velocity and turbulence characteristics scales. The most significant observation is that the flow in the scour holes (intermediate and equilibrium) is found to be plausibly self-preserving.

Item Type:Article
Source:Copyright of this article belongs to American Society of Civil Engineers.
Keywords:Erosion; Open Channels; Turbulent Flow; Submerged Jets; Scour; Sediment Transport; Hydraulic
ID Code:78821
Deposited On:23 Jan 2012 04:01
Last Modified:23 Jan 2012 04:01

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