新疆和田河流域灌丛沙堆风洞流场的实验研究(Ⅱ)  

Study on Wind-tunnel Simulated Flow Pattern over Nabkha Dunes in Hetian River Basin,Xinjiang(Ⅱ)

作　　者：李志忠[1] 武胜利[1] 肖晨曦[1] 刘丽梅[1] 孙秋梅[1] 张中华[1] 

机构地区：[1]新疆师范大学生命与环境科学学院,新疆乌鲁木齐830054

出　　处：《中国沙漠》2007年第1期9-14,共6页Journal of Desert Research

基　　金：国家自然科学基金项目(40461002);教育部科学技术研究重点项目(地方205184);新疆维吾尔自治区高校科研计划基金重点项目(XJEDU2004I35)联合资助

摘　　要：灌丛沙堆是一种重要的风积地貌类型，风力、沙源、植物是影响灌丛沙堆发育的主要因素。依据风沙运动实验相似理论，以新疆和田河流域实测的灌丛沙堆数据为基础，按40：1的比例缩小制作成无植被“灌丛沙堆”模型，在风洞中选用区间在6～14m·s^-1的5组不同风速分别对沙堆模型作纯气流模拟实验流场观测，探讨在不同风力作用下灌丛沙堆表面的流场结构变化特征。模拟实验表明，气流在半球形沙堆迎风坡下部受到正面风压影响有较明显反射涡流，丘顶具有高速气流风蚀区域，而圆锥形沙堆迎风坡气流均匀爬坡加速，背风坡涡流强盛，因此两者在无沙情况下的纯气流流场结构特征、沙堆形态动力平衡特点有较明显差异。Nabkha dune is a kind of typical aeolian landform. The wind power, sand source and plant are the mainly influencing factors of the development of nabkha. In this paper, two models of sand mounds without vegetation were made in 40 ： 1 proportion in wind tunnel, according to similarity theory in wind-sand movement experiments, and on the base of Nabkha data surveyed in the Hetian river basin in Xinjiang. The experimental wind speed are separately 6, 8, 10, 12, 14 m·s^-1. The flow pattern over semispherical sand mound model showed that obvious reflected vortex appeared at the upwind bottom influenced by facade wind pressure, and there was eroded region by strong wind at the top of sand mound. In contrast, the airflow increased equably along the upwind slope of conical sand mound, and vortex at leeward side was very strong. The structure of pure airflow pattern and the dynamic equilibrium point of dune shape are different between semispherical and conical of sand mound.

关 键 词：无植被沙堆 风洞实验 模拟流场 

分 类 号：P931.3[天文地球—自然地理学] X169[环境科学与工程—环境科学]