The interaction between streams and subsurface flows continuously results in an exchange of water and solutes. In order to better describe the flow and transport pro- cesses in the so called hyporheic zone, further research is needed. This study aims to investigate particle transport for an idealised case, which simulates oscillatory flow through a hexagonal closest packed porous media. Furthermore, the influence of the amplitude, the frequency and the diffusion coefficient, by means of the Schmid number, on scalar transport are examined. A three dimensional numerical model is generated with the programming language Julia by using a fully Lagrangian Ran- dom Walk Particle Tracking (RWPT ) approach. The velocity fields for this process were provided by the Associate Professorship of Hydromechanis TUM, which ob- tained the data with a Multi-Grid Large-Eddy Turbulence solver. The simulation domain is a cuboid with periodic boundary conditions and the Neumann boundary condition is applied for the particle interaction with the porous media. The parti- cles are represented as mass-less spheres which assumes instant acceleration by the velocity fields. The most computation time consuming operation of the simulation is the interpolation of the velocities in the spatial and temporal frame. As a fur- ther model simplification the particle-particle interaction is neglected. In order to validate the model, advection and diffusion are modeled separately. The simulation results show that particles transportation is dominated by advection, and therefore are more influenced by the amplitude of the flow field. The superficial bulk velocity corresponds with the mean velocity of the particles in the pore space.     «

The interaction between streams and subsurface flows continuously results in an exchange of water and solutes. In order to better describe the flow and transport pro- cesses in the so called hyporheic zone, further research is needed. This study aims to investigate particle transport for an idealised case, which simulates oscillatory flow through a hexagonal closest packed porous media. Furthermore, the influence of the amplitude, the frequency and the diffusion coefficient, by means of the Schm...     »