Beach evolution and wave dynamics in a Hele-Shaw geometry

In this thesis, the evolution of beach morphologies and the occurrence of breaking waves in a quasi-twodimensional Hele-Shaw geometry were investigated. This research was divided into three parts. Firstly, experiments were performed to study the in uence of single-frequency generated waves on initially flat beds of nearly monodisperse particles. The beds were observed to evolve into a number of possible steady morphology types. The type of steady morphology reached proved to be mainly dependent on the mean depth of the water layer on top of the bed. A detailed study of the internal bed structure showed a continuous rise in packing fraction of the bed in virtually all performed measurements. This was shown to be caused by both a high packing fraction of the redeposited sediment, and the continuous rearrangement of particles in the rest of the bed. Secondly, the occurrence of breaking waves in the Hele-Shaw cell has been investigated. Different types of breaking waves have been observed. The characteristics of these breaker types are very similar to those described by Peregrine [21], of breaking waves observed in nature. Lastly, experiments were performed to validate a numerical model by Gagarina, Van der Vegt, Ambati, and Bokhove [13]. A comparison of potential energies showed very good agreement between experiments and the model.