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Measurements and estimation of flow velocity in mobile bed rills

International Journal of Sediment Research 2023年第1期38卷 97-104页

作者： yunyun ban China Agricultural University Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

Rills are primary sediment sources and hillslope water/sediment runoff transport channels. Water flow velocities in rills are easily affected by bed condition over eroding and non-eroding slopes, which is an important hydrodynamic process in soil erosion research. This research is done to demonstrate the poorly understood “feedback mechanism” related to slope independence of flow velocity to slope gradient. A series of experiments were done on silt loam soil slopes to measure water flow velocity in rills under nine unit width flow rates(q)(0.17 × 10-3, 0.33 × 10-3, 0.67 × 10-3, 1.33 × 10-3, 2.67 × 10-3,5.33 × 10-3, 10.67 × 10-3, 21.33 × 10-3, and 42.67 × 10-3m3/(s·m)) combined with four slope gradients(8.7%, 17.6%, 26.8%, and 36.4%), in which mobile bed rills were monitored. For unit flow velocity under q ≤ 1.33 × 10-3m2/s, independence of flow velocity to slope was obtained. However, the results indicated that slope gradient combined with a higher unit flow rate contributed to better velocity prediction and fitted with a segmented equation well(R2= 0.95). A feedback mechanism was able to verify that the increase in roughness directly dissipated flow energy to reduce flow velocity, but cannot completely counterbalances steep slope effect. The experimental results showed that erosion-caused morphological changes on soil slopes reduce flow velocity by half due to an increase in bed roughness. Therefore, the current experimental measurements considering a wide range of flow rate and slope gradient conditions is useful to reveal the steep slope effect in mobile bed rills. The analysis showed that, for the investigated conditions, the flow velocity is a slope gradient-and flow ratedependent parameter.

关键词： Flow velocity Flow rate Slope gradient Model fitting Slope morphology

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Measuring flow velocity on frozen and non-frozen slopes of black soil through leading edge method

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International Soil and Water Conservation Research 2017年第3期5卷 180-189页

作者： Chao Chen yunyun ban Xuefeng Wang Tingwu Lei College of Water Resources and Civil Engineering China Agricultural UniversityQinghua DongluBeijing100083PR China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationChinese Academy of Science and Ministry of Water ResourcesYanglingShaanxi Province 712100PR China

Flow velocity is a major parameter related to hillslope hydrodynamics erosion.This study aims to measure flow velocity over frozen and non-frozen slopes through leading edge method before being calibrated with accurate flow velocity to determine the correct coefficient for convenience of flow velocity measurement.Laboratory experiments were conducted on frozen and non-frozen soil slopes with flumes involving four slope gradients of 5°,10°,15°,and 20°and three flow rates of 1,2,and 4 L/min with a flume of 6 m long and 0.1 m wide.The measurements were made with a stopwatch to record the time duration that the water flow ran over the rill segments of 2,4 and 6 m long.Accurate flow velocity was measured with electrolyte trace method,under pulse boundary condition.The leading edge and accurate flow velocities were used to determine the correction coefficient to convert the former to the latter.Results showed that the correction coefficient on frozen soil slope was 0.81 with a coefficient of determination(R2)of 0.99.The correction coefficient on non-frozen soil slope was 0.79 with R2 of 0.98.A coefficient of 0.8 was applicable to both soil surface conditions.The accurate velocities on the four frozen black soil slopes were approximately 30%,54%,71%,and 91%higher than those on non-frozen soil slopes.By contrast,the leading edge flow velocities on the frozen soil slopes were 23%,54%,67%,and 84%higher than those on non-frozen soil slopes.The flow velocities on frozen soil slopes increased with flow rate at all four slopes,but they increased from 5 to 15°before getting stabilized.Therefore,rill flow velocity can be effectively measured with leading edge method by multiplying the leading edge velocity with a correction coefficient of 0.80.This study provides a strategy to measure rill flow velocity for studies on soil erosion mechanisms.

关键词： Flow velocity Leading edge method Frozen/non-frozen soil

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Study on the facilities and procedures for meltwater erosion of thawed soil

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International Soil and Water Conservation Research 2016年第2期4卷 142-147页

作者： yunyun ban Tingwu Lei Chao Chen Zhiqiang Liu China Agricultural University Beijing 100083PR China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationCAS and MWRYangling 712100PR China

High erosion rate of seasonal thawed soils by snow-and ice-melting runoff in the high altitude and latitude cold regions has great impacts on ecological systems,industries,agriculture and various manmade infrastructures as well as people's lives.The facilities and procedures are of great importance for the studies on simulating erosion processes of melt-frozen soil.This study focuses on the method and facility for simulating the thawing process of frozen soil.The facility includes soil freezing system,meltwater supply system and experimental flume system for thawed soil erosion.The soil freezing system provides enough space to freeze soil columns in flumes.The water supply system deliveries snow-or icemelting water flow of constant-rate at 0℃.The soil flumes of 200 or 300 cm long,10 cm wide and 12 cm high are designed to be assemble and convenient for soil freezing before they are thawed in one-dimensional manner from top to bottom.The one-dimensional thawing process is realized as follows.The frozen soil flume is put on ice boxes and thermally insulated with heat-insulating materials all around to prevent frozen soil from being thawed from sidewalls and bottom.The soil thaws with this system shows that it can meet the requirements of simulating the process of soil thawing from top to bottom.The thawed soil flumes are connected from end to end to form rills of 6–8 m long to run the erosion experiments under different designed hydraulic condition.The equipment provides facility,method and operation process for simulating one-dimensional soil thawing to serve research on the effect of thawed soil depth on erosion process.

关键词： Melt-frozen Soil erosion Method Facilities Procedures

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AWorldVision

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ChinAfrica 2016年第8期8卷 24-25页

作者： ban Ki-moon Li Yafang Liu yunyun UN Beijing Review 不详

UN Secretary General ban Ki-moon visited China from July 6-10. his lOth trip to the country since assuming office on January 1. 2007. Known for his unwavering determination to bring nations together, ban has always ta... 详细信息

关键词： A World Vision World UN

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东北黑土坡耕地不同水力条件下坡长对土壤细沟侵蚀的影响（英文）

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农业工程学报 2019年第5期35卷 155-162页

作者：陈超雷廷武班云云高晓锋中国农业大学水利与土木工程学院北京100083 中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室杨凌712100

集中水流条件下细沟土壤侵蚀过程对研究细沟侵蚀机理与土壤侵蚀预报有着重要的意义,并且为土壤侵蚀模型其他重要参数比如剥蚀率、可蚀性参数提供基础数据。为了研究东北黑土坡耕地不同水动力条件下坡长对土壤细沟侵蚀的影响,该文采用室... 详细信息

集中水流条件下细沟土壤侵蚀过程对研究细沟侵蚀机理与土壤侵蚀预报有着重要的意义,并且为土壤侵蚀模型其他重要参数比如剥蚀率、可蚀性参数提供基础数据。为了研究东北黑土坡耕地不同水动力条件下坡长对土壤细沟侵蚀的影响,该文采用室内模拟试验方法,测量含沙量随坡长的分布。试验设计包括4个坡度(5?、10?、15?、20?)与3个流量(1、2、4 L/min),在不同水力条件下,测量不同坡长(0.5、1、2、3、4、5、6、7、8m)含沙量。结果表明含沙量在各种水力条件下均随坡长增加,且其增加的速率随坡长减小。对坡长与含沙量系列数据用幂指数函数拟合,其决定系数R2在0.85到0.99之间。因此,黑土坡耕地细沟侵蚀产生的含沙量随坡长呈幂指数增加,且含沙量在一定坡长之后将达到最大值。随坡度和流量的增大,水流在更短的坡长上侵蚀并携带更大的最大含沙量。该文对进一步理解与研究细沟侵蚀过程有着重要的意义,且为深入研究细沟侵蚀提供了数据支撑,为土壤侵蚀模型剥蚀率、可蚀性参数等提供依据。

关键词：土壤侵蚀径流坡长含沙量

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土壤冻结对黄土细沟水流流速的影响

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农业机械学报 2018年第4期49卷 282-289,191页

作者：陈丽燕雷廷武班云云高源中国农业大学水利与土木工程学院北京100083

细沟水流流速是冻土和未冻土坡面水文过程的重要参数,与冻融坡面土壤侵蚀和泥沙输移密切相关。试验在长8 m、宽0.1 m、深0.12 m的土槽内填装深度为0.05 m的陕西安塞黄绵土坡面进行。设定坡度为5°、10°、15°、20°,流量为1、2、4、8 L... 详细信息

细沟水流流速是冻土和未冻土坡面水文过程的重要参数,与冻融坡面土壤侵蚀和泥沙输移密切相关。试验在长8 m、宽0.1 m、深0.12 m的土槽内填装深度为0.05 m的陕西安塞黄绵土坡面进行。设定坡度为5°、10°、15°、20°,流量为1、2、4、8 L/min,通过测量冻土与未冻土坡面细沟水流前锋流经整个土槽所用时间,计算水流的前沿流速,对比2种坡面上水流前沿流速的关系,研究冻结对水流流速的影响,同时采用电解质示踪法计算水流的优势流速,分析优势流速与前沿流速的关系。不同工况下,冻土坡面前沿流速在0.260~0.843 m/s之间,未冻土坡面水流前沿流速在0.175~0.552 m/s之间;冻土和未冻土坡面上,随坡度、流量的增大,前沿流速增大,增大率在缓坡(5°~10°、10°~15°)时逐渐减小,流量较小(1、2、4 L/min)时,流量增大,坡度对前沿流速增大率的影响也逐渐减小;坡度和流量对冻土坡面水流前沿流速的影响大于对未冻土坡面水流前沿流速的影响;冻土和未冻土坡面前沿流速均随坡度和流量的增大近似呈幂函数增大;在试验条件下,冻土坡面前沿流速和优势流速比未冻土坡面大43%和40%;冻土和未冻土坡面上优势流速和前沿流速的比值分别为0.61和0.63,表明该系数可以用于标定前沿流速。试验结果可为冻土坡面与未冻土坡面水流动力过程研究提供参考。

关键词：黄绵土冻土坡面坡面径流前沿流速电解质示踪法

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A DECADE’S DIALOGUE

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Beijing Review 2016年第28期59卷 14-15页

作者： ban Ki-moon UN

UN Secretary General ban Ki-moon visited China on July 6-10,his 10th trip to the country since assuming office on January 1, 2007. Known for his unwavering determination to bring nations together, ban has always taken a hands-on approach to the thorniest issues.His tenure ends this year after leading the UN for a decade.During the Beijing leg of ban’s five-day visit,Beijing Review President Li Yafang and reporter Liu yunyun sat down with the secretary general to talk about his experience and his vision for the world. An edited excerpt of the interview folows:

关键词： ECAD 联合国秘书长对话北京站 ban 编者

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Debunking Lies Scientists from pharmaceutical companies prove U.S.politicians’accusations false

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Beijing Review 2020年第19期63卷 30-30页

作者： Liu yunyun Liang Xiao 不详

"Don’t defend Trump,other than the China Travel ban-attack China."This was what the U.S.Republican Party directed its senatorial candidates to do in a 57-page memo,according to the U.S.media company Politico.The Corona Big Book detailed advice on nearly all potential questions voters may ask such as how to deal with accusations of racism。

关键词： Lies racism Book

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推广胡蜂蜜蜂混合养殖技术确保生物多样性与乡村振兴双赢

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德宏师范高等专科学校学报 2021年第2期30卷 89-92页

作者：党菱婧板芸云梁建平马艳粉德宏职业学院医学技术学院德宏芒市检察院德宏州工信局德宏师专云南芒市678400

昆虫纲膜翅目胡蜂科和蜜蜂科蜂类,分布很广,资源丰富。胡蜂是重要的天敌昆虫,捕食所有森林害虫,可持续控制虫害数量,避免了打农药对生物多样性的影响,同时胡蜂科蜂类和蜜蜂是山区重要的经济昆虫和森林传粉昆虫。但由于胡蜂的捕食特性,... 详细信息

昆虫纲膜翅目胡蜂科和蜜蜂科蜂类,分布很广,资源丰富。胡蜂是重要的天敌昆虫,捕食所有森林害虫,可持续控制虫害数量,避免了打农药对生物多样性的影响,同时胡蜂科蜂类和蜜蜂是山区重要的经济昆虫和森林传粉昆虫。但由于胡蜂的捕食特性,养殖胡蜂和蜜蜂纠纷不断,两败俱伤,所以推广胡蜂蜜蜂混合养殖技术,达到生物多样性保护与乡村振兴双赢的效果势在必行。经过多年的试验研究,我们发明了相关装置,解决了胡蜂、蜜蜂混合养殖的关键技术,促成了胡蜂、蜜蜂混合养殖产业的和谐发展,发挥了人工养殖的天敌昆虫胡蜂科蜂类在生物多样性保护中的绿色防控生态效益和特色经济效益。

关键词：胡蜂蜜蜂混合养殖生态效益

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Debunking Lies

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Beijing Review 2020年第19期63卷 30-30页

作者： Liu yunyun Liang Xiao

Scientists from pharmaceutical companies prove U.S.politicians’accusations false "Don’t defend Trump,other than the China Travel ban-attack China."This was what the U.S.Republican Party directed its senatorial candidates to do in a 57-page memo,according to the U.S.media company Politico.The Corona Big Book detailed advice on nearly all potential questions voters may ask such as how to deal with accusations of racism,as well as how to tie the Democratic

关键词： Debunking Lies

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