Affiliation:
1. State Key Laboratory of Eco‐hydraulics in Northwest Arid Region Xi'an University of Technology Xi'an Shanxi 710048 China
Abstract
AbstractThe influence of density differences on the mixing process of pollutants in the confluence area of the Yellow River (YR) and Fen River (FR) is unclear. This study conducts several field experiments on the hydrodynamic and pollution concentrations in a large asymmetric confluence. The mixing rate and deviation from complete mixing (δ) for the pollutant concentrations are used to describe the mixing process and intensity of contaminants. The results show that the density differences caused by the sediment concentration are an essential factor affecting the pollutant mixing process in the confluence area. After ≈14.7 dimensionless river lengths, theδof the pollutants in the confluence area, under the strong density difference, drops below 10%. In comparison, the maximumδunder the other density differences still exceeds 10% after 27.5 dimensionless river lengths. The strong density difference in the confluence area enhances the pollutant mixing process and shortens the mixing distance. The flow velocity distribution and shear layer changes under different density differences are important driving forces that affect the mixing process of pollutants. This study is of great scientific significance, as it helps gain insight into the mixing pattern of pollutants in river confluence areas.
Funder
National Natural Science Foundation of China
Subject
Pollution,Water Science and Technology,Environmental Chemistry