Parametric study of the dispersion of inertial ellipsoidal particles in a wave-current flow

The degree to which particles such as larvae, seagrass pollen, and microplastics are dispersed by waves and currents influences many ecologically important aspects of their transport and fate. Particle transport models often assume dispersion is simply a function of the local turbulence, but there are many additional parameters related to both the particle characteristics and the flow dynamics that can impact how particles disperse. Here, we perform a parametric study of solutions to the Maxey-Riley equation and Euler's equation for rigid body motion for negatively buoyant, ellipsoidal particles dispersing in a wave-current flow. We systematically examine the impact of a comprehensive set of parameters on particle dispersion: the ratio between the time scales associated with particle settling and the waves, the Archimedes number, the particle eccentricity, the wave steepness, the Keulegan-Carpenter number, and the Stokes number. Our results show that no parameters can be discounted, but that the settling-wave time scale ratio has the largest influence on particle dispersion.