Author(s): Mohammadmehdi Ramezani; Siamak Seyfi; Camillo De Castro; Shooka Karimpour

Linked Author(s): Shooka Karimpour

Keywords: Microplastics; Wake dynamics; Computational Fluid Dynamics; Particle-particle interaction

Abstract: Microplastics are increasingly recognized as persistent contaminants in freshwater environments, yet the physical mechanisms governing their transport, including settling and interaction behaviour, remain poorly understood. This study investigates the settling dynamics and particle–particle interactions of spherical microplastics using a combined numerical and experimental approach. High-resolution large eddy simulations solving the incompressible Navier–Stokes equations coupled with six-degree-of-freedom particle motion are performed, and the resulting particle motions are compared with and validated against in -house particle tracking velocimetry (PTV) experiments. Particle Reynolds numbers are varied numerically through changes in particle density and experimentally through controlled changes in fluid viscosity and density using water– glycerin mixtures. The results indicate that wake-induced interactions play an important role during settling, while the developed numerical–experimental framework provides a basis for systematically exploring interaction regimes and informing improved representations of microplastic transport in ecohydraulic systems.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.337

Year: 2026