Kim, Han Sang (2017-08). Computational Fluid Dynamics Analysis of Non-Cohesive Sediment Transport in Open Channel Flow. Doctoral Dissertation. Thesis uri icon

abstract

  • Predicting sediment transport has numerous implications in Civil Engineering and related fields. When there is excess sediment deposit in waterways, ships that move people and goods cannot navigate them. Loss of sediment that surrounds hydraulic support structures (e.g., bridge piers) may cause structural hazards. In the present dissertation research, computational fluid dynamics (CFD) was applied to improve the prediction capability of sediment transport in turbulent environments, with a focus on open channel flows. The CFD tool used is FANS3D (Finite Analytic Navier-Stokes code for 3D flow), which solves the Reynolds-Averaged form of Navier-Stokes equations in general curvilinear coordinate systems. The code was coupled with sediment transport models to solve the hydrodynamics and the resulting transport phenomena. For flows in domains with complex geometries, the overset grid technique was adopted, wherein multiple blocks with different shapes and structures form the mesh. The wall function approach was implemented to account for roughness effects of the physical domain's boundary surfaces. After validation with experimental results, the coupled model was utilized in four practical applications: transport of suspended sediment in a channel bend, scour around abutment, backfilling of scour hole under a unidirectional flow, and scour around an offshore wind turbine support structure.
  • Predicting sediment transport has numerous implications in Civil Engineering and related fields. When there is excess sediment deposit in waterways, ships that move people and goods cannot navigate them. Loss of sediment that surrounds hydraulic support structures (e.g., bridge piers) may cause structural hazards. In the present dissertation research, computational fluid dynamics (CFD) was applied to improve the prediction capability of sediment transport in turbulent environments, with a focus on open channel flows.

    The CFD tool used is FANS3D (Finite Analytic Navier-Stokes code for 3D flow), which solves the Reynolds-Averaged form of Navier-Stokes equations in general curvilinear coordinate systems. The code was coupled with sediment transport models to solve the hydrodynamics and the resulting transport phenomena. For flows in domains with complex geometries, the overset grid technique was adopted, wherein multiple blocks with different shapes and structures form the mesh. The wall function approach was implemented to account for roughness effects of the physical domain's boundary surfaces. After validation with experimental results, the coupled model was utilized in four practical applications: transport of suspended sediment in a channel bend, scour around abutment, backfilling of scour hole under a unidirectional flow, and scour around an offshore wind turbine support structure.

publication date

  • August 2017