Machine-Assisted Physical Closure for Coarse Suspended Sediments in Vegetated Turbulent Channel Flows

The parameterization of suspended sediments in vegetated flows presents a significant challenge, yet it is crucial across various environmental and geophysical disciplines. This study focuses on modeling suspended sediment concentrations (SSC) in vegetated flows with a canopy density of a(v)H is an element of [0.3, 1.0] by examining turbulent dispersive flux. While conventional studies disregard dispersive momentum flux for a(v)H > 0.1, our findings reveal significant dispersive sediment flux for large particles with a diameter-to-Kolmogorov length ratio when d(p)/eta > 0.1. Traditional Rouse alike approaches therefore must be revised to account for this effect. We introduce a hybrid methodology that combines physical modeling with machine learning to parameterize dispersive flux, guided by constraints from diffusive and settling fluxes, characterized using recent covariance and turbulent settling methods, respectively. The model predictions align well with reported SSC data, demonstrating the versatility of the model in parameterizing sediment-vegetation interactions in turbulent flows.