基于Fluent数值模拟的冰湖涌浪分析——以西藏聂拉木县嘉龙错为例

Numerical simulation of the glacier lake surge based on Fluent:a case study of Jialong Co,Nyalam County,Tibet

冰湖溃决洪水或泥石流(GLOF)是青藏高原主要灾害之一,其形成的灾害链对人民的生命财产安全造成了严重的威胁,其中冰崩导致的冰湖溃决是GLOF的主要灾害形式,但由于其发生位置偏远、间隔时间长、随机性强,导致实地观测资料缺乏,冰崩入湖形成的涌浪机理和过程仍不清晰,而涌浪的规模是GLOF造成下游灾害大小的最主要因素。为分析冰湖涌浪的产生、沿程传播过程和对冰碛坝的爬坡高度,以西藏聂拉木县嘉龙错为例,采用有限体积法,基于流体计算软件Fluent,模拟了嘉龙错补给冰川发生冰崩导致冰湖涌浪的过程。结果表明:数值模拟能较好地对涌浪的产生、规模、沿程传播和对岸爬坡过程进行再现,涌浪初始高度随着冰湖水深、冰体入湖速度和冰体厚度的增加而增大,涌浪高度增加趋势随着冰体入湖速度和冰湖水深的增加而增大,随着冰体厚度的增加而减小。

Glacier lake outburst floods（ GLOF） is one of the major disasters in the Tibetan Plateau,w hich results in a serious threat to people’s life and property. The size of the surge caused by glacier collapse is the most important factor of GLOF. How ever,due to its remote location,long interval time and strong randomness,there is no in-situ observation till now. So far,the research about the size of the surge caused by ice collapse is fruitless till now. By using the finite volume method and CFD softw are Fluent,the surge process of Jialong Co w hen the feeding glacier collapsed has been simulated. Process of the initial surge has been analyzed,as w ell as,the surge w ave propagation along the path and the height of the surge at the opposite bank. The results have been compared with the calculation given by PAN Jiazheng’s method. Finally,it was found that the numerical simulation could w ell reproduce the surge w ave formation,scale,propagation and slope climbing,so it is believed that the simulation w ould provide new ideas for the risk assessment and the study of GLOF.