Research On Numerical Simulation Of Yangshapao Hydrodynamics And Prediction Of Iron Content Distribution

As a precious freshwater resource,lakes have a great impact on human life,and the water environment problems of lakes are becoming more and more prominent.In the 9years after the successful water supply of the Yangshapao project,the water quality has been improved to a certain extent,but the Fe content in the water has not reached the standard value of 0.3mg/l specified in the surface water source standard of centralized domestic and drinking water.Based on the "study on the environmental characteristics of Yangshapao in Western Jilin Water Supply Project(035679)" of Jilin Provincial Water Resources Department,a two-dimensional hydrodynamic model of Yangshapao is established by using Mike21 FM to explore the effects of different wind speeds,different wind directions,different water diversion and ice sheets in different areas on the hydrodynamic characteristics of Yangshapao;After analyzing the current situation of Fe content in ocean sand bubble,combined with its hydrodynamic characteristics,the factors affecting Fe content and distribution are analyzed one by one;Finally,the future development trend of Fe in Yangshapao is studied to provide a theoretical basis for improving the water quality of Yangshapao in the future.(1)Wind is the main driving force of Yangshapao flow field.Under the action of the prevailing wind southwest wind,there are three circulation distributions in the Yangshapao,namely,the counterclockwise circulation in the East,the counterclockwise circulation in the southwest and the clockwise circulation in the north.(2)The Yangshapao flow is mainly composed of wind-driven flow and huff and puff flow,and the Fe content in the lake area will be affected by the distribution of flow field.The stronger the wind speed,the stronger the gale current,the stronger the disturbance to the lake,and the higher the Fe content in the Yangshapao;In the area with small circulation distribution,Fe is difficult to diffuse,resulting in high Fe content in this area;The action range of huff and puff flow generated in the water diversion process is limited,and the dilution area to the Yangshapao water body is also limited.When the Fe content of water diversion is low,it will play a certain dilution role,resulting in the distribution of low Fe content at the inlet of Yangshapao and high Fe content at the outlet,when the content of Fe in diversion water is high,the concentration difference of Fe at inlet and outlet decreases.(3)In winter,the surface of the Yangshapao lake is covered by ice.The larger the ice cover area is,the weaker the wind force on the lake is,the circulation gradually disappears,and the less active the flow field is.As the external disturbance of the lake decreases.After a winter,the Fe content in the water gradually decreases due to sedimentation.Winter is the period when the water quality of the Yangshapao improves.