Multiphase Modelling of Sediment Transport and Bed Erosion for the Study of Coastal Morphodynamics

The protection of coastal areas from erosion is an issue of great importance, not only for the hinterland safety but also for ecological, environmental or other reasons such as the recreational use of the coastal areas. In depth Investigation of key features of coastal erosion, such as the wave-induced sediment transport and the associated bed morphology evolution is inevitable in order to understand this process.

Coastal erosion processes can be examined at many spatial and temporal scales. The main objective of the current research is to examine the detailed scales of sediment transport in order to gain a better understanding of the generating mechanisms of sediment transport and the capturing of processes such as turbulent mixing, particle turbulence interactions and near bottom boundary layer processes.

In 1st stage of this research, a mathematical model based on hybrid two-phase/mixture model is developed. Associated closure equations and two layer turbulence is under development. The resulting model will be implemented into the open source framework OpenFOAM. Wave and current boundary conditions will be applied to idealized test cases to calibrate, validate and test the capabilities of the model.

The 2nd stage aims to upscale the high resolution model results to be applicable to coarse large scale coastal models for engineering applications. Upscaling involves determination of averaged wave/wave-current induced bed shear stress and net sediment flux and development of a new bedload transport model.