沙丘冻结表面风沙传输特征的风洞模拟研究  

Wind tunnel simulation of wind-sand transport characteristics over frozen dune surfaces

作　　者：李锦荣 韩兆恩 崔崴 金筱霖 豆春花 Li Jinrong;Han Zhaoen;Cui Wei;Jin Xiaolin;Dou Chunhua(Yinshanbeilu Grassland Eco-Hydrology National Observation and Research Station,China Institute of Water Resources and Hydropower Research,Beijing 100038,China;School of Public Management,Inner Mongolia University,Hohhot 010021,China;The Water Quality Monitoring Center of Hohhot,Hohhot 010020,China)

机构地区：[1]中国水利水电科学研究院内蒙古阴山北麓草原生态水文国家野外科学观测研究站,北京100038 [2]内蒙古大学公共管理学院,内蒙古呼和浩特010021 [3]呼和浩特市水质监测中心,内蒙古呼和浩特010020

出　　处：《中国沙漠》2025年第1期229-241,共13页Journal of Desert Research

基　　金：国家自然科学基金面上项目(42071021);内蒙古自治区防沙治沙科技创新重大示范工程项目(2024JBGS0013)。

摘　　要：冬季,乌兰布和沙漠的流动沙丘表层10 cm以下土壤会发生冻结。在风力作用下,沙丘表层发生风蚀,部分冻土层裸露,在沙丘上形成冻结“裸斑”与干沙层镶嵌分布的地表,改变着风沙输移过程。为了明确冻结层出现后风沙输移规律变化,通过风洞模拟试验探讨不同风速及水分梯度下非冻结、冻结、干沙+冻结3种情景下的风沙输移特征,揭示土壤冻结对风沙运移的影响。结果表明:(1)3种沙源的输沙率均随着风速增大呈指数增加趋势,随着含水率升高呈指数减小趋势,输沙率与风速及含水率显著相关,输沙率与风速、含水率三者之间符合指数变化规律;(2)冻结作用将输沙率减小3%~91%,当野外冻结“裸斑”出现后,输沙率减小49%~97%;(3)非冻结风沙土沙源输沙率随高度升高而减小,冻结后输沙率随高度的升高呈现先增大后减小的规律,二者函数关系均为指数函数;(4)风蚀发生过程中,出现干沙层与冻土层镶嵌分布时,沙粒由干沙床移动至冻土层界面,沙床面发生变化,跃移输沙增加约18%,输沙率垂直分布呈现先增大再减小的规律,符合幂函数分布,在2~6 cm出现“象鼻效应”。当冬季沙丘出现冻结“裸斑”后,风沙输移有所抑制,同时风沙流中跃移质比例增加。In winter,the soil beneath the top 10 cm of mobile dune surfaces in the Ulan Buh Desert undergoes freezing.Wind erosion of the dune surface layer exposes sections of the frozen soil.This results in a surface with frozen"bare patches"interspersed among dry sand layers,altering the windblown sand transport process.This study employs wind tunnel simulations to investigate the impact of the frozen layer on windblown sand transport patterns.It examines sand transport characteristics under different wind speeds and moisture gradients in three scenarios:non-frozen,frozen,and dry sand combined with frozen conditions.This study reveals how soil freez-ing affects sand transport.The results indicate that:(1)The sand transport rate per unit width of the aeolian sand source and the dry sand combined with frozen source increases exponentially with wind speed and decreases ex-ponentially with water content.Sand transport rate is strongly correlated with both wind speed and water content,following an exponential relationship with both factors.(2)Freezing reduces sand transport rate by 3%to 91%.When"bare patches"appear in the field,the sand transport rate decreases by 49%to 97%.Generally,the sand transport rate of dry sand combined with frozen is greater than that of aeolian sand before freezing,which is greater than that of frozen aeolian sand.(3)Before freezing,the sand transport rate of aeolian sandy soil de-creased with height,but after freezing,it first increased and then decreased with height.The relationship fol-lowed an exponential function.(4)During wind erosion,when the dry sand layer and frozen soil layer are inter-spersed,sand particles move from the dry sand bed to the frozen soil interface,causing changes in the sand bed surface.Saltation transport increases by approximately 18%,and the vertical distribution of sediment transport first increases and then decreases,conforming to a power function.The"trumpet effect"is observed at a height of 2 to 6 cm.When frozen"bare patches"appear on dunes in winter,windblown sand t

关 键 词：冻结层 输沙率 风沙流结构 风洞试验 乌兰布和沙漠 

分 类 号：P931.3[天文地球—自然地理学]