文章摘要
张磊,关见朝,王友胜,胡智丹,王协康.悬移质泥沙输移扩散方程适用条件的讨论[J].水利学报,2018,49(6):694-702
悬移质泥沙输移扩散方程适用条件的讨论
Discussion on the application conditions of diffusion equations of suspended sediment transport
投稿时间:2017-05-26  
DOI:10.13243/j.cnki.slxb.20170649
中文关键词: 悬移质  扩散方程  泥沙浓度  颗粒惯性
英文关键词: suspended sediment  diffusion equation  concentration  particle inertia
基金项目:国家自然科学基金项目(51609264);中国水科院基本科研专项(SE0145B332017;SE0145B702017);国家国际科技合作专项(2015DFR70980)
作者单位E-mail
张磊 中国水利水电科学研究院, 流域水循环模拟与调控国家重点实验室, 北京 100048  
关见朝 中国水利水电科学研究院, 流域水循环模拟与调控国家重点实验室, 北京 100048  
王友胜 中国水利水电科学研究院, 流域水循环模拟与调控国家重点实验室, 北京 100048 wangyousheng@iwhr.com 
胡智丹 水利部水文局, 北京 100053  
王协康 四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065  
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中文摘要:
      悬移质泥沙的输移扩散是泥沙运动力学的基础问题之一,学者们基于不同理论对其运动规律开展了深入研究。基于已有研究,本文主要讨论了不同理论下扩散方程的适用条件。研究结果表明,传统的Rouse扩散方程及其修正式仅适用于泥沙浓度较低、颗粒惯性小至可忽略的条件;两相流理论下的扩散方程由于未考虑颗粒惯性效应,同样只适用于浓度较低、颗粒较小的条件;近期Snehasis Kundul和Koeli Ghoshal基于漂移速度建立的扩散方程由于考虑了升力、颗粒惯性等因素对悬移质分布的影响,使其适用范围相应变大,但在确定泥沙扩散系数上仍然采用的是经验公式,应用上会受到实验资料的限制。基于动理学理论的扩散模型包括基于PDF方程的扩散方程和弥散方程。两个模型中,除了重力沉降和紊流扩散作用外,由于考虑了升力、颗粒紊动、颗粒惯性等影响因素,其在浓度较高、颗粒惯性较大时仍适用,具有普适性。尤其是弥散方程,能够反映颗粒浓度、颗粒紊动、颗粒碰撞等不同机制对泥沙悬浮的影响,全面阐释了悬移质泥沙扩散背后的力学机理。
英文摘要:
      The transport of suspended sediment is one of the important issues in the field of river dynamics,which has been studied by using kinds of theories and methods.In this paper,the application conditions of diffusion equations based on these different theories were discussed.The results show that the traditional diffusion equation and the modified ones is valid when the sediment concentration is low and the particle inertia is small enough;the diffusion equations based on two-phase theory are also applied to the same conditions as the traditional diffusion equation because the inertial effect is not considered.Recently, a diffusion equation proposed by Snehasis Kundu1 and Koeli Ghoshal based on the relation for the drift velocity takes account of effects of lift force,particle turbulence,and particle inertia,which makes this equation suitable for high concentration and large inertia condition.However,the empirical constant is still adapted to determine the sediment diffusion coefficient,which has become the limitation of this model;the diffusion equation derived from the PDF equation and the dispersion equation,both of which are based on the kinetic theory,take account of effects of lift,particle turbulence,particle inertia and other factors on the sediment suspension except the gravitation and the turbulence.Therefore,these two equations can be used in the condition of high concentration and large inertia.Especially,the dispersion equation contains the effects of sediment concentration,the interaction between liquid and solid phase,the particle turbulence and collisions among particles on the sediment suspension,which can illustrate the underlying mechanisms of suspended sediment transport.
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