Author(s): Matthias Kramer

Linked Author(s): Matthias Kramer

Keywords: Plastics Surface detachment Boundary conditions

Abstract: Over the last decade, numerous Lagrangian particle transport models have been used to simulate the transport of plastic particles in marine and fluvial environments. In most numerical studies, plastics are simply assumed as surfaced/trapped once they reach the free surface, and no detachment into suspension has been considered. In this work, a novel theoretical framework for surface detachment of floating plastics is presented. This framework is based on first principles and can be regarded as the surface counterpart to the classical Shields diagram for bed entrainment. A preliminary analysis of the critical detachment velocity, exemplified for cubical particles, shows that the free-surface acts as sink for microplastics, while larger plastics are likely to detach from the interface.

DOI:

Year: 2025