A detached eddy simulation model for the study of lateral separation zones along a large canyon-bound river

Journal of Geophysical Research F: Earth Surface
By: , and 

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Abstract

Lateral flow separation occurs in rivers where banks exhibit strong curvature. In canyon-boundrivers, lateral recirculation zones are the principal storage of fine-sediment deposits. A parallelized,three-dimensional, turbulence-resolving model was developed to study the flow structures along lateralseparation zones located in two pools along the Colorado River in Marble Canyon. The model employs thedetached eddy simulation (DES) technique, which resolves turbulence structures larger than the grid spacingin the interior of the flow. The DES-3D model is validated using Acoustic Doppler Current Profiler flowmeasurements taken during the 2008 controlled flood release from Glen Canyon Dam. A point-to-pointvalidation using a number of skill metrics, often employed in hydrological research, is proposed here forfluvial modeling. The validation results show predictive capabilities of the DES model. The model reproducesthe pattern and magnitude of the velocity in the lateral recirculation zone, including the size and position ofthe primary and secondary eddy cells, and return current. The lateral recirculation zone is open, havingcontinuous import of fluid upstream of the point of reattachment and export by the recirculation returncurrent downstream of the point of separation. Differences in magnitude and direction of near-bed andnear-surface velocity vectors are found, resulting in an inward vertical spiral. Interaction between therecirculation return current and the main flow is dynamic, with large temporal changes in flow direction andmagnitude. Turbulence structures with a predominately vertical axis of vorticity are observed in the shearlayer becoming three-dimensional without preferred orientation downstream.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title A detached eddy simulation model for the study of lateral separation zones along a large canyon-bound river
Series title Journal of Geophysical Research F: Earth Surface
DOI 10.1002/2016JF003895
Volume 122
Issue 1
Year Published 2017
Language English
Publisher AGU Publications
Contributing office(s) Southwest Biological Science Center
Description 25 p.
First page 25
Last page 49
Country United States
State Arizona
Other Geospatial Colorado River