Analyzing the transport process of reacting solute in a wind-affected two-layered laminar open channel flow
Phys. Rev. Fluids 11, 084501 – Published 10 August, 2026
DOI: https://doi.org/10.1103/ylpm-fhrp
Abstract
The transport of solute in a laminar open channel flow through and over a porous layered bed surface has significant applications in natural water resources like rivers, wetlands, and coastal areas. Such research becomes more realistic when the effect of wind, both along and opposite to the flow direction, is considered at the open surface of the water bodies. In this article, we focus on the transport phenomena of tracer molecules in a two-layered channel flow, where the lower layer is filled with a porous medium, under the influence of wind at the upper surface. The present analytical study provides the exchange, advection, and dispersion coefficients, which are valid across all timescales by employing an analytical approach [Sankarasubramanian and Gill, Proc. R. Soc. A 333, 115 (1973)]. Results demonstrate that wind direction critically modulates the transport process: wind-aligned flow enhances advection-driven dispersion, while opposing wind suppresses solute spread, favoring localized retention. Furthermore, an elevated absorption parameter steepens the vertical gradient and confines the solute in the upper region as it moves fast with the wind. Additionally, Brownian dynamics simulations corroborate analytical findings and illustrate particle trajectories under varying wind directions. The insights from this research could help to address water pollution in rivers where the flow field is highly influenced by airflow.
