Eddy‐Controlled Anomalous Transport in Rough Conduits: Physics‐Based Parameterization and Distributed Modeling

Karst conduits play an important role in the process of groundwater and material transport, in which pollutants can move quickly and pollute groundwater easily. Considering the different shapes of karst conduits, hydrodynamic conditions and other factors, eddy generation is very common. After the solute is trapped in the eddy zone, which usually results in the tailing of solutes, typically referred to as non‐Fickian migration or anomalous transport. Many solute transport models have been proposed to explain this phenomenon reasonably and prepare to capture the solute breakthrough curve (BTC), although the model parameters lack a clear physical background. In this study, a series of different types of rough conduits were designed to quantitatively evaluate the influence of eddies on solute transport. A new method for the quantitative identification of the eddy zone is proposed. The quantitative relationship between different flow velocities, roughness shape, relative roughness and the eddy area proportion is summarized. A new model of solute transport under the influence of eddies was proposed based on the traditional mobile‐immobile model, and the physical meaning of the model parameters was clarified. The ability of the new model to capture the breakthrough curve is satisfactory, which can effectively serve the engineered settings.