Numerical simulation of particles beneath a towed circular cylinder

Abstract

This study investigates particle dynamics around a towed circular cylinder near a wall. The flow field obtained from a numerical model based on the Reynolds-Average Navier–Stokes equations is utilized to estimate the particle trajectories computed using a Lagrangian approach. The simulated flow resembles a towed fishing gear and the particles which represent sea stars, muscles, and sediments are seeded at the seabed. The ejection of particles from the seabed is related to the upward flow induced by lee-wake vortex shedding. The effect of the gap between the cylinder and the seabed is investigated, where an increased distance leads to fewer ejected particles and distinct trajectories. Furthermore, for the same relative distance to the seabed, a larger diameter cylinder, and hence a different relative initial position and Reynolds number, leads to fewer ejected particles. The optimal position of the fishing net of a towed fishing gear relative to the cylinder is investigated based on the trajectories.