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Velocity profiles and energy fluctuations in simple shear granular flows

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Particuology 2016年第4期14卷 80-87页

作者： Chuanqi Liu qicheng sun gordon g.D. Zhou State Key Laboratory for Hydroscience and Engineering Tsinghua University Beijing 100084 China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China

Rheology analysis of granular flows is important for predicting geophysical hazards and designing industrial processes. Using a discrete element method, we simulate simple shear flows in 3D under a constant confining pressure of 10 kPa. The inertial number proposed by the gDR MiDi group in France is adopted to distinguish rheology regimes, Both translational and angular velocity profiles are investigated, and both fluid-like and solid-like behavior modes are observed in the flows. The maximum angular velocity occurs near the localized deformation area. We also investigate the energy characteristics of the flows and find that at very small shearing speed, the mean kinetic energy density ek is close to zero, while the mean elastic energy density ec is much greater. At large shearing speed, ek increases. The fluctuating parts of the two types of energy increase with increasing shear speed. Thus, the mean energy density ratio ek/ec can be used in addition to the inertial number to distinguish flow regimes. These results provide insights from energetics into the rheological properties of granular flows.

关键词： Dense granular flows Simple shear Energy fluctuations

Simulations of granular flow along an inclined plane using the Savage-Hutter model

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Particuology 2012年第2期10卷 236-241页

作者： Minglong Fei qicheng sun Deyu Zhong gordon g.D.Zhou State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China

In this work a velocity-dependent friction is introduced into a depth-averaged 5avage-Hutter dynamical model for shallow granular flows. The process of granular material flowing along an inclined plane and then depositing on a horizontal plane is simulated. The surface profiles and evolution of various types of energy are investigated and compared when using the standard Coulomb-type friction versus velocity- dependent friction. Interestingly, there is a small difference between the two different types of friction.

关键词： granular flowsDynamics frictionSavage-Flutter model

Influence of gravity on narrow input forced drainage in 2D liquid foams

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Chinese Science Bulletin 2007年第3期52卷 423-427页

作者： sun qicheng gE Wei HUANg Jin Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China

Liquid foam is a dense packing of gas bubbles in a small amount of liquid containing surfactants or other surface-active macromolecules, which is one of the highly organized materials and possesses hallmark rheological behaviour of soft matters. Forced foam drainage is the flow of constantly inputted liquid through the network of interstitial channels between bubbles under actions of gravity and capil-larity. This process involves two mechanisms: minimal viscous flow dissipation of liquid and minimal surface energy of bubbles. For constant surfactant solution, viscous dissipation usually varies with gravity. This work reports simulations of 2D forced foam drainage with narrow input in a Hele-Shaw cell under 8 different gravities, g, ranging from 9.8 to 0 ms?2. The spread of liquid both vertical due to gravity action, and horizontal due to capillary suction, is recorded over time. Positions of drainage wave fronts in both directions with time are found to be well described in the power law form, and the exponents are 0.536+5.29×10-3g and 0.479?7.27×10-3g, respectively, while the sum is close to a constant of 1.015 which is independent of gravity. For g=9.8 ms-2, the calculated exponents are in good agreement with experimental results by Hutzler et al. and Wang.

关键词：液体泡沫重力效应微重力强制滴流表面能

A preliminary study of the failure mechanisms of cascading landslide dams

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International Journal of Sediment Research 2015年第3期30卷 223-234页

作者： gordon g.D Peng Cui Xinghua Zhu Jinbo Tang Huayong Chen qicheng sun Key Laboratory of Mountain Hazards and Earth Surface Process/Institute of Mountain Hazards and Environment Chinese Academy of Sciences(CAS) CAS Center for Excellence in Tibetan Plateau Earth Sciences State Key Laboratory for Hydroscience and Engineering Tsinghua University

Landslide dams commonly form when mass earth or rock movements reach a river channel and cause a complete or partial blockage of the *** rainfalls can induce upstream flows along a sloping channel that significantly affect downstream landslide *** a series of landslide dams are collapsed by incoming mountain torrents(induced by intense rainfall),large debris flows can form in a very short ***,the failure of these dams can amplify the magnitude and scale of debris flows in the flow *** catastrophic debris flows that occurred in Zhouqu County,China on 8 August 2010 were caused by intense rainfall and the upstream cascading failure of landslide dams along the *** the role of outburst floods associated with the complete or partial failure of landslide dams is an interesting problem usually beyond the scope of analysis because of the inherent modeling *** understand the cascading failure modes of a series of landslide dams,and the dynamic effect these failures have on the enlargement of debris flow scales,experimental tests are conducted in sloping channels mimicking field conditions,with the modeled landslide dams distributed along a sloping channel and crushed by different upstream *** failure modes of three different cascades of landslide dams fully or partially blocking a channel river are parametrically *** study illustrates that upstream flows can induce a cascading failure of the landslide dams along a *** is the primary failure mechanism,while piping and erosion can also induce failures for different constructed landslide dams.A cascading failure of landslide dams causes a gradually increasing flow velocity and discharge of the front flow,resulting in an increase in both diameter and percentage of the entrained coarse ***,large landslide blockages can act to enhance the efficiency of river incision,or conversely to induce aggradation of fluvial se

关键词： Cascading failure Landslide dam Upstream flow Failure mode Landscape evolution Debris flow

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颗粒介质固-流态转变的理论分析及实验研究

力学学报 2016年第1期48卷 48-55页

作者：费明龙徐小蓉孙其诚周公旦金峰清华大学水沙科学与水利水电工程国家重点实验室北京100084 中国科学院水利部成都山地灾害与环境研究所成都610041

颗粒介质由大量离散的颗粒聚集而成,因而与传统固体和流体不同,运动过程中的颗粒介质中可能同时存在多种流态及其相互间复杂的转换过程.颗粒介质弹性失稳机理、不可恢复应变量化是研究颗粒介质固态和流态及固-流态转变的关键.在前期建... 详细信息

颗粒介质由大量离散的颗粒聚集而成,因而与传统固体和流体不同,运动过程中的颗粒介质中可能同时存在多种流态及其相互间复杂的转换过程.颗粒介质弹性失稳机理、不可恢复应变量化是研究颗粒介质固态和流态及固-流态转变的关键.在前期建立的双颗粒温度热力学(two-granular-temperature,TgT)理论基础上,确定了颗粒介质的弹性稳定性条件,建立了不可恢复应变流动法则,搭建了描述颗粒固态-液态及其相互转化的简单模型.颗粒堆积体坍塌过程是典型的颗粒介质固态和流态及其转变过程,因此本文首先开展了25 167个陶颗粒堆积体坍塌过程的实验研究,并使用基于TgT理论的物质点方法和离散元方法对物理实验进行了模拟.结果表明,模型数值结果与物理实验在颗粒堆坍塌过程中的形态、速度分布等细节上吻合很好,同时也发现了现阶段所使用的物质点方法和TgT理论的不足.初步说明TgT理论可以实现颗粒介质固态和流态,以及状态转变的描述.

关键词：颗粒介质热力学物质点法弹性稳定性条件

长白山区图们江流域新生代火山岩的岩石化学研究

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岩石学报 2006年第6期22卷 1481-1490页

作者：王团华樊祺诚孙谦谌宏伟李霓中国地震局地质研究所北京100029 中国地质大学(北京)地球科学与资源学院北京100083

图们江流域新生代火山岩以溢流式喷发为特征,其主要岩石类型以拉斑玄武岩为主,含少量玄武质粗安岩、碱性玄武岩、玄武质安山岩和粗面玄武岩。根据图们江流域火山岩的Mg~#(Mg~#=100Mg^(2+)/(Mg^(2+)+Fe^(2+)))值多数≤60,Ni含量＜100μg/... 详细信息

图们江流域新生代火山岩以溢流式喷发为特征,其主要岩石类型以拉斑玄武岩为主,含少量玄武质粗安岩、碱性玄武岩、玄武质安山岩和粗面玄武岩。根据图们江流域火山岩的Mg~#(Mg~#=100Mg^(2+)/(Mg^(2+)+Fe^(2+)))值多数≤60,Ni含量＜100μg/g和主、微量元素地球化学特征综合表明,形成火山岩的岩浆不是原始岩浆,它们是原始岩浆在上地幔经历了橄榄石、辉石分离结晶作用后形成的以拉斑玄武岩为主,包括碱性玄武岩和粗面玄武岩等演化岩浆,结晶分异作用是岩浆演化过程的主要控制因素。拉斑玄武质岩浆在上升过程中发生了不同程度的壳源物质同化混染作用,发生在上地壳遭受较大程度混染的岩浆K_2O含量明显偏高(＞2．6%),形成玄武质粗安岩。

关键词：图们江流域新生代火山岩火山岩类型岩浆演化

大兴安岭哈拉哈河—淖尔河地区第四纪火山活动初步研究

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岩石学报 2008年第11期24卷 2569-2575页

作者：赵勇伟樊祺诚白志达孙谦李霓隋建立杜星星中国地震局地质研究所北京100029 中国地质大学(北京) 北京100083

大兴安岭中部哈拉哈河淖尔河地区受基底断裂控制,发育28座第四纪火山,这些火山总体呈北东向带状分布。研究区第四纪火山岩分布面积约1000km^2,岩性主要为碱性玄武岩。根据喷发时代和火山地质特征,这里的火山大体可分为更新世和全新世两... 详细信息

大兴安岭中部哈拉哈河淖尔河地区受基底断裂控制,发育28座第四纪火山,这些火山总体呈北东向带状分布。研究区第四纪火山岩分布面积约1000km^2,岩性主要为碱性玄武岩。根据喷发时代和火山地质特征,这里的火山大体可分为更新世和全新世两期。按照火山作用方式不同,区内火山可分为岩浆成因和射汽岩浆成因两类:前者活动产物主要包括火山碎屑锥、碎屑席、熔岩流,其中发育结壳熔岩、渣状熔岩、块状熔岩,以及喷气锥、熔岩冢等火山地质现象;后者产物主要是射汽岩浆喷发形成的基浪堆积物,其中发育大型平行层理及交错层理。不同的火山作用形成了火山口湖、低平火山口湖、火山堰塞湖和塌陷熔岩湖四种不同规模与形态特征的湖泊,这种水火相容的火山地质现象为阿尔山火山温泉国家地质公园增添了景观。

关键词：大兴安岭中部第四纪火山火山地质火山成因湖泊

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钒磷玻璃结构弛豫的DMA测量研究

中国科学：物理学、力学、天文学 2018年第2期48卷 90-96页

作者：段俊杰詹伟涛 HUANg HongNian 姜宏孙其诚李长久王艺臻海南师范大学物理与电子工程学院海口571158 海南大学海南省特种玻璃重点实验室海口570228 The Department of Mathematics and Statistics the University of New MexicoAlbuquerqueNM 87131USA 清华大学水沙科学与水利水电工程国家重点实验室北京100084 海南大学南海海洋资源利用国家重点实验室海口570228

玻璃材料发生屈服和玻璃-液体转变(gLT)之前发生的缓慢结构演化和微观局域暗流的机理至今尚未完全清晰.本文采用动态热机械分析仪系统测量了钒磷二元体系玻璃(V_2O_5-P_2O_5)趋向于玻璃化转变点T_g的动态机械弛豫谱和应力松弛谱,在T_β~... 详细信息

玻璃材料发生屈服和玻璃-液体转变(gLT)之前发生的缓慢结构演化和微观局域暗流的机理至今尚未完全清晰.本文采用动态热机械分析仪系统测量了钒磷二元体系玻璃(V_2O_5-P_2O_5)趋向于玻璃化转变点T_g的动态机械弛豫谱和应力松弛谱,在T_β~483 K和T_ρ~543 K p附近发现了类金属玻璃的α和β结构弛豫和应力松弛行为,结果表明,其与纳米局域钒磷暗流结构的缓慢流动有关.实验首次发现了V_2O_5-P_2O_5玻璃的β弛豫的峰高与驰豫速率符合一定的线性对数关系,即ln(Δ)∞μ-ln(v);基于Wang等人提出的唯像理论模型和稳态流体动力学理论给出了合理的物理图像解释;实验和理论良好符合,进一步证明了V_2O_5-P_2O_5玻璃体系中存在纳米局域钒磷暗流结构及其演化行为的结论.并采用KWW方程的非指数因子β_(KWW)把T_g附近结构演化划分为3个阶段:(1)β_(KWW)0.5 ,宏观流动区.

关键词：钒磷玻璃微观暗流结构弛豫非指数因子动态热机械分析仪(DMA)

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猴头菇中抑菌物质的消除及酸奶的研发

食品工业 2019年第8期40卷 83-86页

作者：孙楚涵卢金桦彭韵霏杨超一栗其成北京农学院

为餐馆饮酒者开发的一款酒后养胃的猴头菇酸奶饮料,利用加热的方式解决猴头菇浆和猴头菇粉中的抑菌物质在酸奶发酵过程中对乳酸菌活性的影响。通过感官评价的方法,优化猴头菇酸奶配方。结果表明,鲜菇浆在100℃以上加热30 min、菇粉在11... 详细信息

为餐馆饮酒者开发的一款酒后养胃的猴头菇酸奶饮料,利用加热的方式解决猴头菇浆和猴头菇粉中的抑菌物质在酸奶发酵过程中对乳酸菌活性的影响。通过感官评价的方法,优化猴头菇酸奶配方。结果表明,鲜菇浆在100℃以上加热30 min、菇粉在110℃以上热风加热60 min,可以有效消除抑菌物质对酸奶品质的不良影响;猴头菇酸奶的最佳配方和工艺条件是:鲜牛乳100 g、全脂奶粉6 g、蔗糖7 g、卡拉胶0.2 g、热处理的菇浆12 g (或菇粉1 g)混合,在95℃条件下杀菌20 min、在42℃下发酵6~8 h,产品品质良好。

关键词：猴头菇猴头菇浆猴头菇粉酸奶