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A Wind Tunnel Investigation of the Shear Stress with A Blowing Sand Cloud

Research in Cold and Arid Regions 2008年第1期 42-58页

作者： zhibao dong Hongtao Wang Guangqiang Qian Wanyin Luo Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhouChina

In a blowing sand system,the wind provides the driving forces for the particle movement while the moving particles exert the opposite forces to the wind by extracting its *** wind-sand interaction that can be characterized by shear stress and force exerted on the wind by moving particles results in the modification of wind *** wind pro-files re-adapted to blown sand movement are measured in a wind tunnel for different grain size populations and at differ-ent free-stream wind *** shear stress with a blowing sand cloud and force exerted on the wind by moving par-ticles are calculated from the measured wind velocity *** results suggest that the wind profiles with presence of blowing sand cloud assume convex-upward curves on the u(z)-ln(z) plot compared with the straight lines characterizing the velocity profiles of clean wind,and they can be better fitted by power function than log-linear *** exponent of the power function ranging from 0.1 to 0.17 tends to increase with an increase in wind velocity but decrease with an increase in particle *** force per unit volume exerted on the wind by blown sand drift that is calculated based on the empirical power functions for the wind velocity profiles is found to decrease with *** particle-induced force makes the total shear stress with blowing sand cloud partitioned into air-borne stress that results from the wind velocity gradient and grain-borne stress that results from the upward or downward movement of *** air-borne stress in-creases with an increase in height,while the grain-borne stress decreases with an increase in *** air-borne shear stress at the top of sand cloud layer increases with both wind velocity and grain size,implying that it increases with sand transport rate for a given grain *** shear stress with a blowing sand cloud is also closely related to the sand transport *** the total shear stress and grain-borne stress on th

关键词： aeolian transport wind-sand interaction air-borne stress grain-borne stress

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Evaluating the optimal porosity of fences for reducing wind erosion

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Research in Cold and Arid Regions 2011年第1期3卷 1-12页

作者： zhibao dong WanYin Luo GuangQiang Qian HongTao Wang Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou Gansu 730000 China

Porosity is the most important parameter determining the shelter efficiency of fences. Wind measurements were made around fence models with different porosities in a wind tunnel. The optimal fence porosity is evaluated by means of Gandemer＇s method that combines the effects of wind reduction and turbulence fields on the shelter efficiency for abating wind erosion. Defining the optimal porosity must take into account of its own purposes, required shelter degree and area to be sheltered. Turbulence has profound impacts on the shelter efficiency of high degree. Two concepts： absolute optimal porosity and practical optimal porosity concerning optimal porosity are proposed. Choosing the practical optimal porosity means reducing cost without significant expense of shelter efficiency. According to the evaluation in present study, the absolute optimal porosity for providing high degree of shelter to abate wind erosion is 0.20 while the practical optimal porosity is around 0.40. Ifa less shelter degree but over wider area is required, the absolute optimal porosity ranges from 0.05 to 0.10 and the practical optimal porosity is 0.10. For any degree of shelter for abating wind erosion effectively, the fence porosity must be less than or equal 0.40.

关键词： windbreak shelter efficiency optimal design

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Threshold wind velocity in the lee of two-dimensional transverse dunes

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Research in Cold and Arid Regions 2010年第1期2卷 1-6页

作者： zhibao dong HongTao Wang GuangQiang Qian WanYin Luo Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou Gansu 730000 China

Secondary flow plays an important role in the development of dunes. To investigate this phenomenon, we simulated models of transverse dunes with different stoss slopes in a wind tunnel. We measured the threshold wind velocity at different locations in the lee of the dunes, and observed the corresponding particle movement characteristics under threshold conditions to assess the sedi-mentological significance of secondary airflow. Threshold wind velocity changed with both horizontal distance and stoss slope. Its variation with horizontal distance is characterized by a region in which a rapid reduction occurs, a region with a minimum value, and a region with high value. We confirmed the presence of reversal cells, irrespective of the stoss slope. Neither the variation in threshold wind velocity nor the variation in reattachment distance as a function of stoss slope followed a monotonic function. The 15° stoss slope had the greatest threshold wind velocity and reattachment distance.

关键词： Aeolian geomoephology dune dynamics transverse dunes

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The wind-saltation interaction in a saltation boundary layer with a downwind air pressure gradient

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Research in Cold and Arid Regions 2010年第5期2卷 384-395页

作者： zhibao dong QingSong Mu GuangQiang Qian WanYin Luo Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chi- nese Academy of Sciences Lanzhou Gansu 730000 China School of Civil Engineering and Mechanics Lanzhou University Lanzhou Gansu 730000 China

Studies of interactions between wind and saltating particles （i.e., the wind-saltation interaction） are usually conducted without consideration of the downwind air pressure gradient. However, in a wind tunnel with limited size, this gradient is required to maintain the movement of the saltation cloud. Attempts are made to investigate the effects of the downwind air pressure gradient on the wind-saltation interaction in a saltation boundary layer based on the experimental results from a wind tunnel with a relatively small cross-sectional area. The wind-saltation interaction is characterized by airborne stress, grain-borne stress, and the force exerted on the wind by the saltation cloud. Basic equations were developed for wind-saltation interactions without and with a downwind air pressure gradient. The results reveal that unacceptable values of negative grain-borne stress and negative force exerted on the wind by the saltation cloud are obtained if the downwind air pressure gradient is ignored. When this air pressure gradient is defined using the measured wind velocity profiles in the presence of saltation and the downwind air pressure gradient is taken into account, reasonable values for grain-borne stress and the force exerted on the wind by the saltation cloud are obtained. These results suggest that attention must be paid to the effects of downwind air pressure gradients when studying the wind-saltation interaction in a wind tunnel. Consideration of the downwind air pressure gradient, inertial forces, and other unidentified variables will provide a more thorough understanding of the interactions within a saltation boundary layer.

关键词： aeolian transport wind-saltation interaction shear stress force

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Driving forces of land use and land cover change (LUCC) in the Zoige Wetland, Qinghai-Tibetan Plateau

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Research in Cold and Arid Regions 2012年第5期4卷 422-430页

作者： GuangYin Hu zhibao dong JunFeng Lu ChangZhen Yan Key Laboratory of Desert and Desertification CoM and Arid Regions Environmental and Engineering Research Institute Chi- nese Academy of Sciences Lanzhou Gansu 730000 China

The Zoige Wetland is located in the northeastern Qinghai-Tibetan Plateau, which is highly sensitive to global environment change and human disturbance because of its high elevation and cold environment, thus, it＇s a hotspot for land use and land cover change （LUCC） research. We used Landsat MSS images from 1975, Landsat ETM images from 2000, and Landsat TM images fi：om 1990 and 2005 to assess the LUCC in the study area, using GIS techniques, as well as topographic, vegetation, and soil maps combined with field investigations. The monitoring result shows that the study area＇s environment degraded rapidly between 1975 and 2005, including wetland shrinkage from 5,308 km2 to 4,980 lan2, sandy land expansion from 112 krn2 to 137 krn2, forest land decreasing from 5,686 km2 to 5,443 km2, and grassland degradation from 12,309 km2 to 10,672 km2. According to the analysis of meteorological data and social-economic statistical data, we concluded that the LUCC in the Zoige Wetland was caused by both natural and anthropogenic factors, but human activities were primarily responsible for the observed LUCC, thereby, we suggest human behaviors must be adjusted to control environmental degradation.

关键词： Zoige Wetland LUCC remote sensing environmental degradation Qinghai-Tibetan Plateau

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An investigation of the effects of dust storms on rat lung using HRCT and blood gas analysis

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Research in Cold and Arid Regions 2016年第4期8卷 319-324页

作者： FengFeng Lei WanYin Luo zhibao dong YingZhu Sang LiZhu Luo Gang Huang Hua Liu QiZhang Chen Department of Respiration the People's Hospital of Gansu Province Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Department of Radiation Imaging the People's Hospital of Gansu Province

The increasing intensity and frequency of sand-dust storms in China has led to greater prominence of associated environmentaland health issues. Many studies have focused on the health effects of air particulate contaminants, but fewformal investigations have studied the effects of sand-dust storms on human and animal health. The aim of this study wasto investigate the effects of dust storms on rat lung by using high resolution computed tomography （HRCT） and blood gasanalysis through a wind tunnel simulating. We found that the rat lung damage effects can be detected by the HRCT imagingafter exposure to sand-dust storm environments, but had no obvious result through blood gas analysis. Exposure durationspositively correlated with the damage degree to lung tissue. These will provide some evidence for clinical diagnosis ofnon-occupational pneumoconiosis.

关键词： dust storm lung blood gas analysis HRCT wind tunnel simulation

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A descriptor for the local dust storm occurrence probability constituted by meteorological factors

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Research in Cold and Arid Regions 2012年第2期4卷 140-153页

作者： WanYuan Li ShiHua Lu zhibao dong ShiGong Wang zhibao Shen YuChun Chen Ye Yu YinHuan Ao Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou Gansu 730000 China Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou Gansu 730000 China Key Laboratory for Semi-Arid Climate Change of the Ministry of Education Lanzhou University Lanzhou Gansu 730000 China

Based on daily data sets of 17 meteorological factors during the period of 1954-2005 for 60 gauge stations distributed over Gansu Province of China and the corresponding dust storm records, the dust storm probabilities related to different classes of each factor have been calculated and analyzed. On the basis of statistical analysis, a meteorological descriptor quantifying the daily dust storm occurrence probability for each station, which is referred to as the Dust Storm Occurrence Probability Index （DSOPI）, has been effectively established. According to the statistical characteristics of DSOPI for each station, a feasible judging criterion for a dust storm event has been determined, which can greatly contribute to forecasting dust storms and completing the unavailable historic dust storm records. Meanwhile, the average daily dust storm probability related to each factor on the dust storm day for each station has been specially analyzed in detail, finally disclosing that, in general, the more signifi- cant one factor＇s influence on dust storms, the greater its contribution to them; and each factor＇s contribution clearly varies from place to place. Moreover, on average, maximum and mean wind speeds, maximum-speed wind direction, daily sunny hours, evaporation, mean and lowest relative humidity, lowest surface air pressure and vapor pressure contribute to dust storm events in Gansu Province most greatly in order among all the 17 involved factors.

关键词： meteorological factor dust storm occurrence significance probability index contribution

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Momentum profile of aeolian saltation cloud

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Research in Cold and Arid Regions 2009年第1期1卷 25-29页

作者： zhibao dong WanYin Luo GuangQiang Qian HongTao Wang Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhouGansu 730000China

The momentum profile of an aeolian saltation cloud is poorly understood. In this paper, height profiles for saltation momentum are reconstructed for three particle-size populations at four wind velocities based on profiles for mean particle velocity and relative particle concentration of saltation cloud obtained using particle image velocimetry in a wind tunnel. The results suggest that the saltation momentum profiles are characterized by peak curves with a maximum at some height above the surface. The height of this maximum increases with increasing wind velocity, but decreases with increasing particle size. It is linearly correlated with average saltation height and is comparable with the results of numerical simulations in a previous study. Our results confirm that Bagnold’s kink is an important feature of wind velocity profiles modified by the presence of saltating particles and that the height of the kink is closely related to the average trajectories of the saltating particles.

关键词： aeolian saltation cloud momentum profile wind tunnel test

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Discussion on the Symbiosis of Barchan Dune and Linear Dune in Asia

Discussion on the Symbiosis of Barchan Dune and Linear Dune ...

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作者： Weikang SHI zhibao dong Rina SA School of Geography and Tourism Shaanxi Normal University

Symbiotic dunes are not only distributed in many deserts on earth,but may also exist on Mars and other *** this paper,we measure the morphological parameters of symbiotic areas of barchan dunes and simple linear dunes in Asia through Google Earth satellite *** development environment,morphological combination characteristics and the wind regime of symbiotic dunes were analyzed to further understanding the causes of their *** result shows that there are 23 symbiotic dunes regions,which exist in 7 desert areas in Asia,however,are mainly distributed in the Qaidam Basin Desert and the Rub al Khali *** morphological parameters of symbiotic dunes have a certain difference both in regional and single ***,for Qaidam Basin Desert,there are maximum morphological parameters,which may cause by the larger mean wind velocity in this *** formation of symbiotic dunes is affected by two or more different factors including the wind regime,Sediment Salinity,obstacles and *** this investigation,we have a comprehensive understanding on the formation process of symbiotic dunes,furthermore,enrich and broaden the current theory of aeolian geomorphology.

关键词： barchan dune linear dune symbiotic dune

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深空探测时代的风沙地貌学

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地球科学进展 2019年第10期34卷 1001-1014页

作者：董治宝吕萍陕西师范大学行星风沙科学研究院

"深海、深地、深空"探测为地球科学发展提供了机遇与挑战,地球科学开始迎接以火星探测为代表的深空探测高潮。中国将于2020年实施火星探测计划,对火星开展全球性、综合性的环绕探测,并对局部地区开展巡视探测。行星地学研究,包括风沙地... 详细信息

"深海、深地、深空"探测为地球科学发展提供了机遇与挑战,地球科学开始迎接以火星探测为代表的深空探测高潮。中国将于2020年实施火星探测计划,对火星开展全球性、综合性的环绕探测,并对局部地区开展巡视探测。行星地学研究,包括风沙地貌学,需要未雨绸缪,做好准备。基于风沙地貌学的发展历史与趋势,将发展历史划分为只关注风沙地貌本身的经典研究、关注地球系统的现代研究和关注地外星球的未来研究3个阶段,总结了各阶段的特点,认为深空探测时代的行星风沙地貌学研究已水到渠成。随之重点总结了行星风沙地貌学的发展与成就,指出亟待解决的问题,展望未来发展方向。现已探明在火星、金星和土卫六上有多种类型风沙地貌发育,风成过程甚至是这些星球最活跃的现代表面过程。不同星球风沙地貌具有较好的相似性,但差异也很明显,意味着风沙地貌发育机理的统一性和形成条件的多样性,风沙地貌学理论需要通过不同星球风沙地貌的对比研究逐步完善和拓展。地外行星上较为简单的形成条件在展示风沙地貌形成规律和机理方面具有明显优势,深空探测时代的风沙地貌学方兴未艾。

关键词：深空探测风沙地貌金星火星土卫六

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