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Analysis of Solute Entrapment and Dispersion in a Meandering Channel, Bye Dye Trace and Image Acquisition Techniques

Author(s): Sergio Saul Solis; Ian Guymer; Richard Dutton

Linked Author(s): Ian Guymer

Keywords: DE; ADZ; Hart; Transient Storage; Dispersion

Abstract: Flow visualization techniques have always played a major role in elucidating flow processes. A series of experiments were carried out within a 234-degree meandering sand channel. Dye trace testing (fluorometery) and digital capture of images under induced fluorescent conditions were employed. Three modelling approaches were used to evaluate the development of temporal solute profiles, namely the Advection Dispersion Equation (ADE), the Aggregated Dead Zone (ADZ) and a transient storage model developed by Hart (1995). Six flow discharges were tested. The assessment included an analysis of solute entrapment from the recorded image sequences. Discrete Areas of Interest (AOI) from the storage zones, mainstream and channel transverse averaged concentration profiles were evaluated. The storage ratios suggest an increase in the relative storage as the flow discharge is reduced. Three characteristic dispersion coefficient trends were observed when using discrete AOI from channel averaged ones. The dominant mixing processes within this channel are the solute retention created from the development of storage zones and secondary circulation, which were directly linked to the longitudinal changes in channel shape and flow stage.


Year: 2013

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