Numerical Simulation Of The Glacier Lake Surge Of Jialong Co

As the continued rising of global temperature,glacier lake outburst disasters occur frequently,and the Glacier Lake Outburst Flood(GLOF)causes a series of mountain disasters such as debris flow,which results in a serious threat to human's life and property in the plateau area.There are many inducements for GLOF,and the surge caused by ice avalanche/snowslide or glacial landslide collapsing into the lake is the direct inducing factor for GLOF in plateau area.There is no in-situ observation till now.So far,the research on the size of the surge caused by glacier collapse is fruitless.Therefore,the research on the prediction of glacier lake surge can provide new idea and reference for the risk assessment and the study of GLOF.The research contents and results are as follows.(1)Firstly,this dissertation establishes a two-dimensional model of Jialong Co in Nyalam County,Tibet,based on the similarity criterion and with a scale of 1:1.By using CFD code ANSYS/FLUENT,the surge process of Jialong Co is simulated when the feeding glacier collapses and the process of the initial surge,the surge wave propagation along the path and the height of the surge at the opposite bank are analyzed.Then this dissertation compares many empirical estimation methods with experimental method,and summarizes their advantages and disadvantages,which shows that the model is feasible for analyzing the glacier lake surges.(2)The numerical results show that when the feeding glacier collapses,the initial surge reaches its peak at 4.87 s,and up to 67.4 m.Later,the surge propagation would attenuate obviously.At 60.6 s,the surge propagates to the terminal moraine dam,climbing height reaches 10.9 m,and lots of water from glacial lake overtopping the dam.(3)This dissertation analyzes the changes of pressure and velocity fields in the basin caused by the feeding glacier collapse.It is found that entry point has the maximum dynamic pressure and the strongest air billow,so it may lead to the widest range of disasters.This provides a certain practical reference value when taking effective prevention and control measures for GLOF.(4)Based on the previous studies,combined with the actual conditions of Jialong Co,four several factors such as different velocity,different depth of water,different angle of entering the water and different ice thickness are selected to simulate the scale of glacier lake surge under four different conditions.The analysis results show that the height of initial surge increases with the increase of water depth,ice velocity,angle of entering water and ice thickness.The increasing trend of surge height increases with the ice velocity and the water depth,but decreases with the increase of ice thickness and angle of entering the water.