Flow dynamics at a river confluence on Mississippi River: field measurement and large eddy simulation

ORAL

Abstract

We study the dynamics of a river confluence on Mississippi River branch in the city of Minneapolis, Minnesota, United States. Field measurements by Acoustic Doppler Current Profiler using on-board GPS tracking were carried out for five campaigns in the summer of 2014 and 2015 to collect both river bed elevation data and flow fields. Large Eddy Simulation is carried out to simulate the flow field with the total of 100 million grid points for the domain length of 3.2 km. The simulation results agree well with field measurements at measured cross-sections. The results show the existence of wake mode on the mixing interface of two branches near the upstream junction corner. The mutual interaction between the shear layers emanating from the river banks leading to the formation of large scale energetic structures that leads to ``switching'' side of the flow coherent structures. Our result here is a feasibility study for the use of eddy-resolving simulations in predicting complex flow dynamics in medium-size natural rivers.

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Authors

  • Trung Le

    Saint Anthony Falls Laboratory, University of Minnesota

  • Ali Khosronejad

    St. Anthony Falls Lab. University of Minnesota, Saint Anthony Falls Laboratory, Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, Saint Anthony Falls Laboratory, University of Minnesota

  • Nicole Bartelt

    Minnesota Department of Transportation

  • Solomon Woldeamlak

    Minnesota Department of Transportation

  • Bonnie Peterson

    Minnesota Department of Transportation

  • Petronella DeWall

    Minnesota Department of Transportation

  • Fotis Sotiropoulos

    St. Anthony Falls Lab., University of Minnesota, St. Anthony Falls Lab. University of Minnesota, Saint Anthony Falls Laboratory, Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, Univ of Minn - Minneapolis, University of Minnesota, St. Anthony Falls Laboratory, University of Minnesota, Saint Anthony Falls Laboratory, University of Minnesota