Open-source model/data

A Multi-dimensional Eulerian two-phase model for sediment transport:

SedFoam 1.0: A multi-dimensional numerical model for sediment transport based on the two-phase flow formulation is developed. With closures of particle stresses and fluid-particle interaction, the model is able to resolve processes in the concentrated region of sediment transport and hence does not require conventional bedload/suspended load assumptions. The numerical model is developed in three spatial dimensions. However, in the existing versions, the model is only validated for Reynolds-averaged two-dimensional vertical (2DV) formulation. This numerical model is developed via the open-source CFD toolbox, OpenFOAM and the new solver is called SedFoam. We gratefully acknowledge developers involved in OpenFOAM, which is the foundation of SedFoam. This study is supported by National Science Foundation (CMMI-1135026; OCE-1356855) and Office of Naval Research (N00014-14-1-0586, Littoral Geosciences and Optics Program).

Download SedFoam 1.0 from CSDMS model repository

CACR report

SedFoam 1.0 Clinic in 2015 CSDMS Annual Meeting (YouTube video)

SedFoam 2.0 is now available! Through close collaboration with researchers (Dr. J. Chauchat’s group) at LEGI, Grenoble-INP, SedFoam 2.0 can be downloaded via a dedicated website maintained by LEGI. This version included several different options on turbulence closure and rheologcial closures and more importantly a much comprehensive documentation, including tutorials. UD component of the study is supported by National Science Foundation (OCE-1635151; OCE-1537231) and Office of Navel Research (N00014-16-1-2853).

More info on downloading SedFoam 2.0

GMD paper for SedFoam 2.0

Free-surface resolving Eulerian two-phase model for sediment transport, SedWaveFoam 1.0:

Kim, Y., Cheng, Z., Hsu, T.-J., & Chauchat, J. (2018). A numerical study of sheet flow under monochromatic nonbreaking waves using a free surface resolving Eulerian two-phase flow model. Journal of Geophysical Research: Oceans, 123, 4693–4719.

Abstract: We present a new methodology that is able to concurrently resolve free surface wavefield, bottom boundary layer, and sediment transport processes throughout the entire water column. The new model, called SedWaveFoam, is developed by integrating an Eulerian two-phase model for sediment transport, SedFoam, and a surface wave solver, InterFoam/waves2Foam, in the OpenFOAM framework. SedWaveFoam is validated with a large wave flume data for sheet flow driven by monochromatic nonbreaking waves. To isolate the effect of free surface, SedWaveFoam results are contrasted with one-dimensional-vertical SedFoam results, where the latter represents the oscillating water tunnel condition. Results demonstrate that wave-averaged total sediment fluxes in both models are onshore-directed; however, this onshore transport is significantly enhanced under surface waves. Onshore-directed near-bed sediment flux is driven by a small mean current mainly associated with velocity skewness. More importantly, progressive wave streaming drives onshore transport mostly in suspended load region due to an intrawave sediment flux. Further analysis suggests that the enhanced onshore transport in suspended load is due to a “wave-stirring” mechanism, which signifies a nonlinear interaction between waves, streaming currents, and sediment suspension. We present some preliminary efforts to parameterize the wave-stirring mechanism in intrawave sediment transport formulations.

Acknowledgement: This study is supported by NSF (OCE-1635151 and OCE-1356855) and Office of Naval Research (N00014-16-1-2853). Numerical simulations presented in this study were carried out using the Mills cluster at University of Delaware, and the SuperMic cluster at Louisiana State University via XSEDE (TG-OCE100015). Z. Cheng would like to thank the support of postdoctoral scholarship from Woods Hole Oceanographic Institution. We are grateful to the developers involved in OpenFOAM, who are the foundation of the model presented in this paper.

The source code of SedWaveFoam and the case setup to reproduce the same results are publicly available via GitHub:

SedWaveFoam 1.0 code

Case setup for Dohman-Janssen and Hanes (2002,

Fine sediment transport simulation in the wave bottom boundary layer:

Cheng, Z., X. Yu, T.-J. Hsu, C. E. Ozdemir, and S. Balachandar (2015a), On the transport modes of fine sediment in the wave boundary layer due to resuspension/deposition: A turbulence-resolving numerical investigation, J. Geophys. Res. Oceans, 120, 1918–1936, doi:10.1002/2014JC010623.

Abstract: Previous field observations revealed that the wave boundary layer is one of the main conduits delivering fine sediments from the nearshore to continental shelves. Recently, a series of turbulence-resolving simulations further demonstrated the existence of a range of flow regimes due to different degrees of sediment-induced density stratification controlled by the sediment availability. In this study, we investigate the scenario in which sediment availability is governed by the resuspension/deposition from/to the bed. Specifically, we focus on how the critical shear stress of erosion and the settling velocity, can determine the modes of transport. Simulations reveal that at a given wave intensity, which is associated with more energetic muddy shelves and a settling velocity of about 0.5 mm/s, three transport modes, ranging from the well-mixed transport (mode I), two-layer like transport with the formation of lutocline (mode II) and laminarized transport (mode III) are obtained as the critical shear stress of erosion reduces. Moreover, reductions in the settling velocity also yield similar transitions of transport modes. We also demonstrate that the onset of laminarization can be well-explained by the reduction of wave-averaged bottom stress to about 0.39 Pa due to attenuated turbulence by sediments. A 2D parametric map is proposed to characterize the transition from one transport mode to another as a function of the critical shear stress and the settling velocity at a fixed wave intensity.

Acknowledgement: This work is supported by National Science Foundation (OCE-1130217) and Office of Naval Research (N00014-14-1-0586) to the University of Delaware and National Science Foundation (OCE-1131016) to the University of Florida. Simulations presented in this paper are carried out on Chimera (CNS-0958512) and MILLS at the University of Delaware and the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant No. TG-OCE100015.

Download FineSed3D (Version 1.0), through Community Surface Dynamics Modeling System (CSDMS) code repository.

A newer version of the turbulence-resolving fine sediment transport model is current under development. The document details the preliminary numerical modeling framework can be downloaded here.

  3D Large-eddy simulation (LES) of breaking waves in the surf zone

  1. Zhou, Z., Sangermano, J., Hsu, T.-J., Ting, F. C. K., (2014) A numerical investigation of wave-breaking-induced turbulent coherent structure under a solitary wave, J. Geophys. Res., 119 (10), 6952-6973. DOI: 10.1002/2014JC009854.

    Abstract: To better understand the effect of wave-breaking-induced turbulence on the bed, we report a 3D Large-Eddy Simulation (LES) study of a breaking solitary wave in spilling condition. Using a turbulence-resolving approach, we study the generation and the fate of wave-breaking-induced turbulent coherent structures, commonly known as obliquely descending eddies (ODEs). Specifically, we focus on how these eddies may impinge onto bed. The numerical model is implemented using an open-source CFD library of solvers, called OpenFOAM, where the incompressible 3D filtered Navier-Stokes equations for the water and the air phases are solved with a finite volume scheme. The evolution of the water-air interfaces are approximated with a volume of fluid method. Using the dynamic Smagorinsky closure, the numerical model has been validated with wave flume experiments of solitary wave breaking over a 1/50 sloping beach. Simulation results show that during the initial overturning of the breaking wave, 2D horizontal rollers are generated, accelerated and further evolve into a couple of 3D hairpin vortices. Some of these vortices are sufficiently intense to impinge onto the bed. These hairpin vortices possess counter-rotating and downburst features, which are key characteristics of ODEs observed by earlier laboratory studies using Particle Image Velocimetry. Model results also suggest that those ODEs that impinge onto bed can induce strong near-bed turbulence and bottom stress. The intensity and locations of these near-bed turbulent events could not be parameterized by near-surface (or depth integrated) turbulence unless in very shallow depth.

    Acknowledgement: This study is supported by National Sceince Foundation (CMMI-1135026; OCE-1356855). Simulations are carried out on MILLS and CHIMERA at the University of Delaware. Funding for CHIMERA was supported by the National Science Foundation (CNS-0958512). Simulations also leverage computing resource provided by Extreme Science and Engineering Discovery Environment (XSEDE) (TG-OCE100015).

    Simulations: Numerical simulation is carried out using OpenFOAM (version 1.7.1). Simulation setup can be downloaded here.

  2. Kim, Y., Z. Zhou, T.-J. Hsu, and J. A. Puleo (2017), Large eddy simulation of dam-break-driven swash on a rough-planar beach, J. Geophys. Res. Oceans, 122, doi:10.1002/2016JC012366.

Abstract: Turbulence characteristics in the swash zone are investigated using a 3-D large eddy simulation model. The numerical model is implemented based on OpenFOAM which solves the filtered Navier-Stokes equations for two immiscible fluids with a standard Smagorinsky subgrid-scale closure. The numerical model is validated with laboratory data for swash flow driven by a dam-break apparatus. The model results demonstrate that the main characteristics of turbulence in the swash zone are different from those in the surf zone, which are mainly induced by surface wave breaking. During uprush phase, bore-generated turbulence has 2-D turbulence characteristics because of limited water depth. Near-bed-generated turbulence is mainly observed during backwash. Turbulence production and turbulent dissipation rate estimated from the model results indicate an imbalance, possibly due to advection at swash front and large roughness used. Touching down of turbulent coherent structure (TCS) is observed during uprush, which drives intense bed shear stress. During the backwash, interaction between TCS and bed is less clear. However, finger-like patterns in the spatial extent of bed shear stress and vertical components of vorticity are predicted during the backwash. The location of the strongest finger patterns in the vertical direction is collocated with that of maximum turbulence production. These finger patterns are likely caused by boundary layer instabilities injected vertically from the bed.

Acknowledgement: This study is supported by NSF (OCE-1356855; OCE-1332703; OCE-1537231) and Office of Naval Research (N00014-16-1-2853). Numerical simulations presented in this study were carried out using the Mills cluster at University of Delaware, and the SuperMic cluster at Louisiana State University via XSEDE (TG-OCE100015). Laboratory data of O’Donoghue et al. [2010] are greatly appreciated.

Simulations: Numerical simulation is carried out using OpenFOAM (version 1.7.1). Simulation setup can be downloaded here.

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