你的位置:水利论文 >> 论文 >> 江苏省 >> 南京水利科学研究院 >> 详细内容 在线投稿

波或流作用下高强度非粘性推移质输运规律研究 【作者】王玉海 【导师】喻国华

热度137票 浏览90次 【共6条评论】【我要评论 时间:2006年7月01日 19:20

Mgo;FY&kuw0波或流作用下高强度非粘性推移质输运规律研究
o?%t XB-r*N0水利论文|:K"^3^a!E

;Qo$FOMb(q-}t0【作者】王玉海导师喻国华水利论文sV6V+b;@ST"r
【作者基本信息】南京水利科学研究院,港口、海岸及近海工程,2006年,博士

Crar\QqfF0水利论文c$[jlH z_2x;J

水利论文P)}3Ee3Q9S$Z
【中文摘要】 高强度非粘性推移质输沙过程经常发生于河道行洪、河口与海岸地区的风暴潮或暴风浪期间,引起岸滩剧烈演变和航道骤淤等问题。因此,如何准确地预测和预报强波浪或强水流条件下推移质的输沙量成为学术界和工程界关注的核心问题之一。自法国工程师Du Boys于1879年提出水流对推移质的拖曳力模型和相应的输沙率公式后,学者们基于不同的技术路线先后提出了若干推移质输沙率公式。但是,已有的大部分公式均为经验或半经验公式,公式的系数固定并且依赖于得出它们的有限试验数据,因而这类公式的应用范围有限。虽然有学者从连续介质力学的角度,将高强度输沙过程中由泥沙颗粒和孔隙水组成的固—液混合体处理为牛顿流体或其它类型的流体,从而构建相应的数学模型,并由此出发讨论颗粒的运动速度,“流深”等的计算公式和提出若干复杂程度不同的推移质输沙率公式;但是有关公式并未得到试验或实测资料的验证,最大程度上也只能说是定性地正确。究其原因,一方面在于这些理论模型多是从微观角度入手分析单颗粒泥沙的受力情况并跟踪其运动轨迹同时借助于气体分子运动论的研究成果而构建的,因而这类模型无法考虑在高强度输沙过程中颗粒之间密集的相互碰撞作用对颗粒群体输沙行...更多为的影响;另一方面,这些模型在应用Bagnold(1954)应力关系式时,常常不正确地将其处理为水流剪切应力与颗粒间的法向离散应力的关系,不符合推移质输运的物理实质。另外,现有的经验、半经验公式均不能有效考虑地形坡度和水流中含泥量多寡等因素对推移质输沙率的影响。有鉴于此,本项研究根据复杂性科学研究中所倡导的系统论、整体论的思想,基于连续介质力学的有关理论,选取高强度推移质输运过程中的特征尺度,考虑了固—液混合体运动过程中上下两个交界面的受力作用,构建了刻画高强度推移质输运的理论模型。本项研究将理论分析及高强度水槽输沙试验和数值试验相结合,取得了如下一系列研究成果:1.构建了高强度推移质输运过程中固—液混合体运动的数学模型(偏微分方程组)。该模型由质量连续方程和运动方程组成。2.寻求了该理论模型对应于“动平床”的一个特解,并得到了1D推移质输沙率的理论计算公式;在明确了推移层内颗粒浓度和速度分布后,得到了一个可用于实际计算的1D推移质输沙率公式。该公式的系数表现为一个能够随着水流和泥沙条件的改变自动进行调整的函数关系式,能够自然地考虑地形坡度和水流中含泥量(冲泻质)多寡等因素对输沙率的影响,从而克服了现有经验、半经验公式的局限性。该公式得到了大量水槽试验资料和现场实测数据良好的验证。同时,基于水流边界层对数流速分布规律,构建了计算推移层表层颗粒运动速度的公式并进行了充分验证。3.利用有限差分数值方法—WAF方法(Weighted Averaged Flux method),求解了该偏微分方程组解的一般特征。通过设定的斜坡输沙受扰的数值试验,探讨了恒定流作用下高强度输沙过程中固—液混合体运动的稳定性问题。结果发现,在恒定流作用下的推移层当受到局部扰动后其表面会失去稳定,形成动力波,即波高、波长不断加大而波速不断减小直至发生破碎。此外,该数值试验揭示出分层剪切流体“界面波”或者“内波”发育演化的可能情形。4.基于波浪边界层内水流流速对数分布规律的假定,构建了计算波浪边界层摩擦系数的公式。该公式具有物理概念清晰,结构形式简单、易于使用等特点。基于“准恒定”的思想,将有关研究成果拓展为非对称波浪作用下临底高含沙层内推移质净输沙率的计算公式,利用大型波浪水槽中非破碎非对称波,大型往复流水道中非对称波和天然海滩上波浪上爬区破波作用下均匀沙和非均匀沙输沙率实测资料对该公式进行了良好验证。总之,本项研究构建的刻画高强度推移质输运过程固—液混合体运动规律的数学模型是成功的,计算推移层表层颗粒运动速度和波浪边界层摩擦系数等公式也是成功的,所获得的单向流或非对称波浪作用下的高强度推移质输沙率公式可以尝试在工程实践中应用。  还原

Vl'^xn,t0

x&Zt9Z*h,Q8Y!_1^0【英文摘要】 Intense transport of non-cohesive bedload sediments often occurs in rivers in flood, in estuarine and coastal waters in storm conditions, causing significant morphodynamic evolution, rapid siltation of harbors, navigation channels and other problems. Therefore, it is of great importance to be able to predict bedload transport rate in strong currents or big wave regime with high accuracy for the coastal engineering community.Since Du Boys in 1879 suggested drag-force model and related bedload transport rate formula, investigators have proposed possibly over one hundred bedload formulas using various approaches. Nonetheless, the majority of these formulas are empirical and semi-empirical with fixed coefficients that were regressed from a limited number of experimental and field data. This has seriously limited the application scope of such formulas. Some investigators tried to build mathematical models by treating the intense transport of mixture consisting of bedload particles and inter...更多-particle fluid as Newtonian fluid or other types of fluid based upon continuum mechanics, and derived formulas for calculating particle velocity, bed thickness, etc. However, most of the results could only be claimed qualitatively correct and the few transport rate formulas derived in this way have not been accepted by the engineering community.The reasons are, on one hand, these theoretical models only analyzed the force exerted on a single particle and follows its movement tract from a microscopic perspective with the molecular kinematic theory, this led the models to be unable to take account into the effect of the intense interparticle collisions upon transport behavior of particle assemblage; on the other hand, these models often incorrectly treated Bagnold's (1954) stress relation as relation between water flow shear stress and the normal dispersive pressure arising from interparticle collisions.In addition, the existing empirical, semi-empirical transport rate formulas could not effectively take into account the effect of bed slope, wash-load concentration in driving water, and other factors on bedload transport rate.In view of these, the present study attempts to build a theoretical model to describe the intense transport of non-cohesive bedload sediment using system theory, holism theory and continuum mechanics and fully considering the forces acting upon the upper and lower boundary surface of the sediment-water mixture as it moves.The present study is conducted through theoretical analysis supplemented with bedload transport flume experiment and numerical experiments. The major results are:1. Has built a theoretical model (partial differential equations, PDEs) to describe the intense transport of bedload sediment-water mixture. The model consists of a mass conservation equation and a momentum equation, belonging to a nonlinear hyperbolic conservation system.2. Has sought the special solution to the model that corresponds to the "plane-bed regime" in bedload transport processes. Using a 'UCH' approach this solution is transformed into a 1D theoretical bedload transport rate formula. Its coefficient appears to be a dynamic function that could generically take account into the hydrodynamic and sediment property, in particular of the effects of bed slope (positive and negative), wash-load concentration in the dilute water column upon the bedload transport rate. After specifying the particle velocity and concentration profiles in the mixture layer and how to calculate the dynamic frictional angle of particles, etc. the 1D theoretical formula can be used to predict bedload transport rate. It compares very well with large flume experiment and field observation datasets. Worthy mentioning, the present study suggests a formula to determine the particle velocity at the top of bedload layer on the basis of logarithmic velocity distribution in a current boundary layer. It is calibrated with extensive flume experimental data.3. Using finite difference numerical scheme-Weighted Average Flux method (WAF) that is proficient in solving Riemann discontinuity problem, the present study successfully solved the PDEs. Through prescribed numerical experiments in which a steady flow of sediment-fluid mixture is disturbed by a hump upon an incline, the present study discusses the stability of the mixture flow. It finds: the surface of mixture driven by a steady current will lose stability due to the local disturbance, and dynamic waves appear and evolve downstream with growing wave height and wave length but diminishing wave speed until they break. The numerical experiments disclose the occurrence of interface wave or internal wave in stratified flows consisting of shearing water flow and the high-concentration mixture flow once the latter is disturbed locally. The numerical code was executed in MATLAB environment.4. Assuming a logarithmic velocity distribution in the wave boundary layer, the present study obtains a formula for determining the wave friction factor that is used to compute the Shields parameter. This formula has advantages of solid physical basis, simple structure and easy usage in comparison with other existing formulas. Based upon the special solution of the PDEs the present study obtains a 1D bedload formula to predict the net transport rate in a wave cycle in sheet-flow regimes driven by asymmetric waves. This bedload formula compares well with the experimental data obtained from a large-scale wave flume (Grober WellenKanal, GWK of the ForschungsZentrum Küste, Hannover) and a large-scale oscillatory water tunnel (Delft Hydraulics) as well as field observation in the Myalup beach, Australia.  还原水利论文zZDf"] F:FY @"l!n7y

水利论文{`(t Mts

【中文关键词】 非粘性推移质; 恒定流; 非对称波浪; 动平床; 临底高含沙层; 理论模型; 输沙率公式; 水槽试验; 数值试验水利论文w*JA:L~])f
【英文关键词】 non-cohesive bedload; steady current; asymmetric waves; plane bed; sheet flow; theoretical model; transport rate formula; flume experiment; numerical experiment水利论文2S `5z9dp0l4s
水利论文#R @ Ue'_s)N

水利论文(b&PuN8tQi

 水利论文D z8Y0Dc y|i

TAG: 导师 推移质 王玉海 喻国华 高强度
顶:12 踩:18
【已经有107人表态】
19票
极差
12票
很差
10票
较差
13票
稍差
10票
稍好
11票
较好
13票
很好
19票
极好
下一篇:江滩人工湿地植物对泥沙及污染物的去除机理及应用研究【作者】郭长城 【导师】喻国…
上一篇:圆柱桩群阻力特性及其对底床冲淤影响的研究 【作者】邓绍云 【导师】陈志昌
水利论文安徽省电信网友 [lkad5fdb] ip: 117.67.*.*
2015-09-18 20:53:55
You do  <a href="http://www.shopthecardinalsjerseysonline.com/Elite-Kareem-Martin-Cardinals-Jersey/">Kareem Martin Jersey</a> not need <a href="http://www.shopthecardinalsjerseysonline.com/Elite-John-Abraham-Cardinals-Jersey/">Authentic John Abraham Jersey</a>  to take these risks to obtain the attractive bronze coloration that many desire. The influence of electronic media is adversely affecting the demand for toys largely.In spite of all the magical  <a href="http://www.shopthecardinalsjerseysonline.com/Elite-Drew-Stanton-Cardinals-Jersey/">Authentic Drew Stanton Jersey</a> Kareem Martin Jersey cures touted in magazine articles and golf videos, the only way Authe
水利论文IANA网友 [nypd1doi] ip: 223.240.*.*
2015-11-14 17:25:04
Shoulder and chest straps: Don't underestimate the importance of good sho <a href="http://www.footballraidersofficial.com/women-clive-walford-jersey/">Clive Walford Authentic Jersey</a> ulder straps.  Related articlesbaike. Y <a href="http://www.footballraidersofficial.com/women-curtis-lofton-jersey/">Curtis Lofton Jersey</a> ou will need to do something drastic to make the team building activity successful and productive for the company as a whole reaching the vision and mission of the company with ease and c <a href="http://www.footballraidersofficial.com/women-nate-allen-jersey/">Raiders Nate Allen Jersey</a> o
水利论文Unknown网友 [nypd1doi] ip: 183.160.*.*
2016-02-07 01:54:21
Two or three drops of cinnamon oil, mixed with a teaspoon of honey, also  <a href="http://www.officialsteelers.us.com/Black-Jason-Worilds-Steelers-Jersey.html">Jason Worilds Jersey</a> give vast relief.Sore throat means the inflammation of the pharynx (bac <a href="http://www.officialsteelers.us.com/Black-Wesley-Johnson-Steelers-Jersey.html">Wesley Johnson Steelers Jersey</a> k of the throat).Other Accessories Other Than Your Main GarmentsThere are many occasions,Jason Worilds Jersey, where you feel like something is still missi <a href="http://www.officialsteelers.us.com/Black-Ben-Roethlisberger-Steelers-Jersey.html">Authentic Ben Roethlisberger Jersey</a> n
水利论文Unknown网友 [dlsr90xc] ip: 183.160.*.*
2016-05-30 17:48:01
With th <a href="http://www.basketballwarriorsshop.com/Warriors-Kevon-Looney-Finals-Jersey/">Authentic Kevon Looney Jersey</a> e sma <a href="http://www.basketballwarriorsshop.com/Warriors-Klay-Thompson-Finals-Jersey/">Klay Thompson Finals Jersey</a> rt sensors, you would definitely be able to do so and much more. The cloud user interfe adopts a major city chart to ow off the severity of environnt toxi <a href="http://www.basketballwarriorsshop.com/Warriors-David-Lee-Finals-Jersey/">David Lee Warriors Jersey</a> ns. With the smart sensors,Authentic Kevon Looney Jersey, you would definitely be able to do so and much more.Works well. More often t
水利论文安徽省电信网友 [nypd1doi] ip: 117.67.*.*
2016-07-14 13:04:06
I think (what <a href="http://www.mlbangelsteamshop.com/authentic-reggie-jackson-angels-jersey/">Reggie Jackson Jersey</a>  will happen) is  <a href="http://www.mlbangelsteamshop.com/authentic-garrett-richards-angels-jersey/">Angels Garrett Richards Jersey</a> that the big bears will eventually take over the space. Mercury - countants, book sellers, tehers, authors and the mathematicians. S <a href="http://www.mlbangelsteamshop.com/authentic-cj-wilson-angels-jersey/">C.J. Wilson Authentic Jersey</a> ummaryOklahoma University has discovered innovative approach for online and offline classroom sessions to groom each student in a perfect
水利论文安徽省电信网友 [dj2gyqgr4c] ip: 117.68.*.*
2016-11-02 12:10:58
Name your foods after our most-liked plumbing so their tale and on <a href="http://www.shoptheofficialbengals.com/Elite-Andre-Smith-Bengals-Jersey/">Andre Smith Jersey</a> line game escapades.As it is, Los Angeles needs offense m <a href="http://www.shoptheofficialbengals.com/Elite-Kevin-Huber-Bengals-Jersey/">Kevin Huber Bengals Bengals Jersey</a> ore than starting pitching at this point.Not an all in one great deal regarding drivers can afford for more information about are obligated to pay that on the town frequently p <a href="http://www.shoptheofficialbengals.com/Elite-Jeremy-Hill-Bengals-Jersey/">Jeremy Hill Bengals Bengals Jersey</a> a
查看全部回复【已有6位网友发表了看法】

广告投放

广告投放