Flow and dispersion characteristics of sediment plumes induced by a moving vehicle in deep-sea mining

Deep-sea mining disturbs benthic sediments, generating plumes that can mobilize heavy metal ions and pose ecotoxicological risks to marine ecosystems. Understanding the associated wake and plume dynamics is therefore crucial for environmental impact assessment. This study develops a novel particle–turbulence interacting Eulerian (PT–Euler) model, which modifies governing-equation source terms to resolve PT interactions. Model validation shows less than 5% deviation in key concentration fields and good agreement in plume morphology with experimental data. Simulations investigate the trailing plume dispersion from a mining vehicle, focusing on the dimensionless vehicle speed (Vn: the ratio of vehicle movement speed to sediment discharge speed; Vn = 0–2) and initial sediment concentration (αs = 0.009–0.030). Results show that both factors significantly affect dispersion, with speed dominating the pattern and concentration exerting a secondary modulation. Higher speed promotes plume rise and horizontal spread, while increased sediment concentration suppresses these trends. Vehicle motion induces near-field uplift through entrainment and enhances far-field advective transport via the wake. Flow separation and wake recirculation generate strong vortices that amplify ascent; at higher speeds, vortex-induced confinement in the near-field transitions to a pronounced downstream “transport effect” in the far-field. These findings provide critical insights for evaluating and mitigating the environmental impacts of deep-sea mining operations.