Collective dynamics of confined nanoparticles in nanochannel flow

Molecular dynamics simulations were performed to investigate particle-fluid flow in argon-filled nanochannels, focussing on the role of nanoparticle (NP) size and concentration. Copper NPs with diameters of 3, 5, and 7 nm were introduced in nanochannels containing 4, 8, and 12 NPs to analyze collective transport. Results show that increasing NP size and number reduces the average fluid velocity and flattens the velocity profiles, indicating enhanced momentum dissipation due to solid–fluid interactions. NP mobility arises from the combined effects of advection and Brownian motion, with diffusion coefficients decreasing as the NP number increases. Interfacial analysis reveals the formation of solid-like argon layers surrounding the NPs, which move coherently with the particles and effectively increase their hydrodynamic size, leading to greater drag. These findings provide atomistic insight into how confinement and collective NP effects govern transport, diffusion, and interfacial structuring in particle-laden nanoflows.