A Model for Mass Transport Across the Sediment-Water Interface

Abstract

Molecular diffusion, dispersion, and turbulent diffusion can all contribute to the transport of mass across the sediment-water interface (SWI). Flow observations across the SWI are critical in the description of these transport processes but are currently very limited as the sediment bed is inaccessible in most experimental approaches. We overcome this constraint by combining refractive-index matching (RIM) with particle-tracking velocimetry (PTV). Using measurements of the flow dynamics across the SWI, we propose a mechanistic model that describes the interfacial mass transport over a wide and relevant parameter space. We show there are three transport regimes where molecular, dispersive, o..