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Velocity and Concentration Profiles of Saline and Turbidity Currents Flowing in a Straight Channel Under Quasi-uniform Conditions : Volume 1, Issue 1 (18/11/2013)

By Stagnaro, M.

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Book Id: WPLBN0004007828
Format Type: PDF Article :
File Size: Pages 37
Reproduction Date: 2015

Title: Velocity and Concentration Profiles of Saline and Turbidity Currents Flowing in a Straight Channel Under Quasi-uniform Conditions : Volume 1, Issue 1 (18/11/2013)  
Author: Stagnaro, M.
Volume: Vol. 1, Issue 1
Language: English
Subject: Science, Earth, Surface
Collections: Periodicals: Journal and Magazine Collection, Copernicus GmbH
Publication Date:
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

Description: Department of Civil, Chemical and Environmental Engineering, University of Genova, Genova, Italy. We present a series of detailed experimental observations of saline and turbidity currents flowing in a straight channel. Experiments are performed by continuously feeding the channel with a dense mixture until a quasi-steady configuration is obtained. The flume, 12 m long, is characterized by a concrete fixed bed with a uniform slope of 0.005. Longitudinal velocity profiles are measured in ten cross sections, one meter apart, employing an Ultrasound Doppler Velocimeter Profiler. We also measure the density of the mixture using a rake of siphons sampling at different heights from the bottom in order to obtain the vertical density distributions in a cross sections where the flow already attained a quasi-uniform configuration. We performed 27 experiments changing the flow discharge, the fractional excess density, the character of the current (saline or turbidity) and the roughness of the bed in order to observe the consequences of these variations on the vertical velocity profiles and on the overall characteristics of the flow. Dimensionless velocity profiles under quasi-uniform flow conditions were obtained by scaling longitudinal velocity with its depth averaged value and the vertical coordinate with the flow thickness. They turned out to be influenced by the Reynolds number of the flow, by the relative bed roughness, and by the presence of sediment in suspension. Unexpectedly the densimetric Froude number of the current turned out to have no influence on the dimensionless velocity profiles.

Velocity and concentration profiles of saline and turbidity currents flowing in a straight channel under quasi-uniform conditions

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