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A Refined Formulation for Eddy Viscosity with Integrated Effects of Vortex Formations Due to Shear Instability

Author(s): Ichiro Kimura; Takashi Hosoda; Michiaki Iwata; Shinichiro Onda

Linked Author(s): Ichiro Kimura, Shinichiro Onda

Keywords: Shear instability; Turbulence model; Depth-averaged shallow flow equations

Abstract: We developed a new depth-integrated RANS (Reynolds Averaged Navier Stokes equation) type turbulence model for simulating open channel flows with large scale unsteady vortex formations due to the shear instability. The basic concept of this approach is that the eddy viscosity is set locally larger where the magnitude of turbulence intensity is increased due to the large scale vortex shedding. The present model is validated through the comparison with the experimental data by Chu and Babarutui (1988) [1]in parallel shear open channel flows with two-lanes of different velocities. The computational results showed that the present novel approach can predict excellently the velocity profiles around the shear layer even if a coarser computational grid, which cannot resolve the large scale vortex formations, is applied.

DOI:

Year: 2016

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