The Transport of Microplastic Pollution by the Ocean’s Waves at Moderate Stokes Numbers

Activity: Talk or presentationOral presentation


In recent decades, plastic pollution in the global oceans has been a growing issue. Specifically, microplastics
(plastic particles smaller than 5mm in diameter) are of special concern, and there is an observed sizedependent
preferential loss of microplastics from the ocean surface to the water column [1]. However, the
mechanism behind this process is not fully understood. The movement of microplastics in the global oceans
can be modelled using the Maxey-Riley equation, and present models of microplastic transport rely on
neglecting the Basset-Boussinesq history term and the assumption of infinitely deep water [2]–[4]. However,
the history term can only be neglected for microplastics with a diameter smaller than approximately 50μm.
Thus, existing models that neglect the Basset-Boussinesq history term cannot be applied to sufficiently large
microplastic particles.
In this presentation, we compare previous models that neglect the history term. Additionally, we compare
the analytical and numerical methods used in the models to compute the Stokes drift velocity. We explore
techniques for including the Basset-Boussinesq history term, such as mapping the problem to a forced, timedependent
Robin boundary condition of the 1-D diffusion equation and solving with unitary transforms as
described in [4]. Using these techniques, we examine the effect that the history term has on particles with
moderate Stokes numbers.
Period24 May 2023
Event title36th Scottish Fluid Mechanics Meeting 2023
Event typeConference
LocationGlasgow, United KingdomShow on map
Degree of RecognitionNational