Sediment Disturbance and Near-Field Dispersion Characteristics of a Coandă-Effect Collector

Balancing high collection efficiency and controlled sediment plume dispersion is a core challenge in deep-sea polymetallic nodule harvesting technology. This work investigates a Coandă-effect collector using two numerical frameworks: a CFD-DEM model for water–nodule interaction, and a Eulerian two-fluid model embedded with non-Newtonian thixotropic rheology for sediment erosion and near-field plume dispersion. Rheological parameters were calibrated via rotational rheometer tests, and the numerical framework was independently validated against laboratory water tank experiments under two typical disturbance modes, showing good agreement in both plume morphology and erosion pit geometry. On the basis of the validated model, extended numerical predictions were conducted to analyze the effects of four key parameters on collection performance and sediment disturbance, with the underlying governing mechanisms elucidated. The results reveal the variation trends of erosion intensity, plume scale, and collection efficiency with each parameter, providing a preliminary numerical reference for the structural design and operational optimization of low-disturbance Coandă-effect collectors.