基于有效剪力的Delft3D泥沙输运模型改进及应用OA

Oriented to estuarine digital twins,this study addresses the systematic overestimation of suspended sediment concentration by the default Delft3D sediment module,which stems from a mismatch between its grain size partitioning and transport formula selection and the"two-phase"water-sediment dynamics of estuar-ies.We propose two improvements:(1)considering the dynamic interconversion among bed material,bed-load,and suspended load under turbulent bursting,the empirical grain-size threshold is eliminated,enabling the transport terms and the particle-size spectrum—capturing both fine-particle flocculation and coarse-grain initiation—to be solved collaboratively within a unified framework;and(2)an effective-shear extension algo-rithm is introduced to eliminate the dependence on channel gradient,thereby making the corresponding sedi-ment-carrying capacity formula applicable to tidal and other unsteady processes.Using the Yalu River Estuary as a case study,the numerical experiments show that the improved model fits suspended-sediment concentra-tion better than the default configuration and more realistically reproduces erosion-deposition patterns.Moreo-ver,the sediment-carrying-capacity formula employs fixed theoretical parameters without manual calibration,yielding stronger robustness and portability of the improved model.By explicitly accounting for the flocculation of fluid-mud components typical of estuaries,the proposed scheme substantially enhances Delft3D's applica-bility and decision-support capability in estuarine digital-twin applications.