CSDMS 2014 annual meeting - Uncertainty and Sensitivity in Surface Dynamics Modeling

The SAFL Virtual StreamLab (VSL3D): High Resolution Simulation of Turbulent Flow, Sediment Transport, and Morphodynamics in Waterways

Fotis Sotiropoulos

University of Minnesota, United States
Ali Khosronejad University of Minnesota United States

The St. Anthony Falls Laboratory Virtual StreamLab (VSL3D) is a powerful multi-resolution and multi-physics Computational Fluid Dynamics (CFD) model for simulating 3D, unsteady, turbulent flows and sediment transport processes in real-life streams and rivers with arbitrarily complex structures, such as man-made hydraulic structures, woody debris, and even hydrokinetic turbine arrays. The code can handle arbitrarily complex geometry of waterways and embedded structures using novel immersed boundary strategies. Turbulence can be handled either via Reynolds-averaged Navier-Stokes (RANS) turbulence models or via large-eddy simulation (LES) coupled with wall models. Free-surface effects are simulated using a level-set, two-phase flow approach, which can capture complex free-surface phenomena, including hydraulic jumps, over arbitrarily complex bathymetry. A fully-coupled hydro-morphodynamic module has also been developed for simulating bedload and suspended load sediment transport in meandering rivers. A novel dual time-stepping quasi-synchronized approach has been developed to decouple the flow and sediment transport time scales, enabling efficient simulations of morphodynamic phenomena with long time scales, such as dune migration in rivers. The code is parallelized using MPI. This clinic will present a comphrehensive overview of the VSL3D, report extensive grid sensivity and validation studies with experimental data, and present a series of applications, including: 1) LES and unsteady RANS of turbulent flow and scalar transport in natural meandering streams; 2) LES of sand wave growth and evolution in a laboratory scale flume; 2) unsteady RANS of dune formation and migration in large scale meandering rivers with in stream rock structures (rock vanes, j-hooks, w-weirs, etc.); 3) LES of free-surface flows in natural and enginnered open channels; and 4) LES of gravity currents.

Representative references about the VSL3D code

1. Khosronejad, A., Hill, C., Kang, S., and Sotiropoulos, F., “Computational and Experimental Investigation of Scour Past Laboratory Models of Stream Restoration Rock Structures,” Advances in Water Resources, Volume 54, Pages 191–207, 2013.

2. Kang, S., and Sotiropoulos, F., “Assessing the predictive capabilities of isotropic, eddy-viscosity Reynolds-averaged turbulence models in a natural-like meandering channel,” Water Resources Research, Volume: 48, Article Number: W06505, DOI: 10.1029/2011WR011375, 2012.

3. Kang, S., Khosronejad, A., and Sotiropoulos, F., “Numerical simulation of turbulent flow and sediment transport processes in arbitrarily complex waterways,” Environmental Fluid Mechanics, Memorial Volume in Honor of Prof. Gerhard H. Jirka, Eds. W. Rodi & M Uhlmann, CRC Press (Taylor and Francis group), pp. 123-151, 2012.

4. Kang, S., and Sotiropoulos, F., “Numerical modeling of 3D turbulent free surface flow in natural waterways,” Advances in Water Resources, Volume: 40, Pages: 23-36, DOI: 10.1016/j.advwatres.2012.01.012, 2012.

5. Kang, S., and Sotiropoulos, F., “Flow phenomena and mechanisms in a field-scale experimental meandering channel with a pool-riffle sequence: Insights gained via numerical simulation,” Journal of Geophysical Research – Earth Surface, Volume: 116, Article Number: F03011 DOI: 10.1029/2010JF001814 Published: AUG 20 2011.

6. Khosronejad, A., Kang, S., Borazjani, I., and Sotiropoulos, F., “Curvilinear Immersed Boundary Method For Simulating Coupled Flow and Bed Morphodynamic Interactions due to Sediment Transport Phenomena,” Advances in Water Resources, Volume: 34, Issue: 7, Pages: 829-843 DOI: 10.1016/j.advwatres.2011.02.017, Published: JUL 2011.

7. Kang, S., Lightbody, A., Hill, C., and Sotiropoulos, F., “High-resolution numerical simulation of turbulence in natural waterways,” Advances in Water Resources, Volume 34, Issue 1, January 2011, Pages 98-113.

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Of interest for:
  • Terrestrial Working Group
  • Hydrology Focus Research Group