Rans-Based Numerical Simulation of Wave-Induced Sheet-Flow Transport of Graded Sediments

David R. Fuhrman, Ugur Caliskan

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Abstract

An existing one-dimensional vertical (1DV) turbulence-closure flow model, coupled with sediment transport capabilities, is extended to incorporate graded sediment mixtures. The hydrodynamic model solves the horizontal component of the incompressible Reynolds-averaged Navier–Stokes (RANS) equations coupled with k–ω turbulence closure. In addition to standard bed and suspended load descriptions, the sediment transport model incorporates so-called high-concentration effects (turbulence damping and hindered settling velocities). The sediment transport model treats the bed and suspended load individually for each grain fraction within a mixture, and includes effects associated with increased exposure of larger particles within a mixture. The model also makes use of a modified reference concentration approach, with reference concentrations computed individually for each fraction, and then translated to a common level, which conveniently enables use of a single computational grid for the simulation of suspended sediments. Parametric study shows that these effects combine to help alleviate an otherwise systematic tendency towards over- and under- predicted transport rates for fine and coarse sand fractions, respectively. The sediment transport model is validated against experimental sheet-flow measurements conducted in oscillatory tunnels beneath velocity-skewed wave signals, and demonstrates similar accuracy (predicted transport rates generally within a factor of two of measurements) for both graded mixtures and uniform sands.
Original languageEnglish
Publication date2017
Number of pages10
Publication statusPublished - 2017
EventCoastal Dynamics 2017 - Helsingør, Denmark
Duration: 12 Jun 201716 Jun 2017

Conference

ConferenceCoastal Dynamics 2017
CountryDenmark
CityHelsingør
Period12/06/201716/06/2017

Keywords

  • Sediment transport
  • Graded sediments
  • Non-uniform sediment mixtures
  • Wave boundary layer
  • k-w turbulence model

Cite this

Fuhrman, D. R., & Caliskan, U. (2017). Rans-Based Numerical Simulation of Wave-Induced Sheet-Flow Transport of Graded Sediments. Paper presented at Coastal Dynamics 2017, Helsingør, Denmark.