高含沙明渠紊流光滑区f—Re关系与平均流速公式

本文根据水槽试验结果，从紊动与絮网结构相互影响的角度分析了光滑区内阻力系数ｆ与有效雷诺数Ｒｅ关系散乱的原因；通过分析ｆ与断面平均流速Ｖ的关系，建立了高含沙明渠紊流光滑区平均流速公式，并作初步分析。     

曼宁公式与对数流速公式的转换关系

本文采用综合论证法建立了Δ／Ｒ＝ｆ（ｎ√ｇ／Ｒ＾１／６）的关系，见正文式（１４），以现有的试验资料论证了该式在平整粗糙床面符合Δ＝Ｄｃｐ的规律，适用范围较宽（４＜Ｒ／Δ＜２５０００）。引用张长高的圆管紊流新模式，在式（１４）的基础上，改进了普朗特尔的标准对数模式，把明渠和圆管的紊流水力光滑区、过渡区以及粗糙区的平均流速公式、圆管流速分布公式统一为一式，对明渠流速分布统一公式进行了初步探讨，分析了边     

长江口徐六泾站潮流测验资料分析方法探讨

在大量实测资料的基础上，对潮流测资料进行了初步的分析和探讨。方法是依据全潮测验的全过程资料，对垂线平均流速组合优化，分析垂线流速阴潮痊变变化的分布形态，从而建立不同相对水深的点流速与垂线平均流速的关系，为点线换算提出定量数据，进而建立垂线平均流速与断面平均流速关系并推算潮流量。     

流量在线测验垂线布设方案探析 ——以前垾村水文站为例

为研究坐底式ADCP在线流量测验方案,根据多元回归法,利用Matlab统计分析工具箱,分析了前垾村水文站句容河断面主泓的垂线流速与断面平均流速的相关关系,并对模型进行了检验.重点研究单根垂线的流速与断面平均流速相关关系模型的随机误差以及2根垂线的流速与断面平均流速相关关系模型的随机误差,分析结果为该站流量在线测验方案实...     

潮流量在线监测方法与实践研究

潮流量测验是一项十分复杂的工作，采用常规流速仪测流技术，不能实时连续监测完整的潮流量过程。采用指标流速连续在线监测与走航式声学多普勒流速仪流量测验相结合的测验模式，通过指标流速与断面平均流速建立关系进行潮流量计算，可以实现潮流量在线监测。主要对潮流量在线监测模式、测验仪器及在深圳河应用做了研究分析，讨论了指标流速合理性分析方法，提出了通过指标流速与断面平均流速建立关系进行潮流量整编，并结合深圳河的潮流量在线监测应用情况提出了其应用前景。     

光滑圆管进口段紊流边界层发展

光滑圆管进口段紊流边界层的研究在理论和实践上都具有十分重要的意义。本文在流速分布符合对数律和指数律的假设下,通过求解卡门边界层动量积分方程获得了光滑圆管进口段紊流边界层发展的计算式,并建议了光滑圆管紊流边界层发展区的平均流速计算式。同时对指数n与参数(u_*δ)/v的关系也进行了探讨。     

流量在线监测在九江水文站的可行性分析

九江水文站地处长江中游末端，其下游9km 处有张家洲将长江分为南北两江；其下游30km 有鄱阳湖入汇长江，对本站水位、流量有顶托影响，水位～流量关系不稳定。为了提高流量整编成果的精度和报汛准确性，需找出能代表流量测验断面平均流速的代表性垂线流速，进而可实行在线流量监测。根据九江水文站垂线平均流速横向分布以及多年断面图，以该站2017 年至2021 年ADCP 实测流量成果资料为依据，对测速垂线进行了指标流速多元线性回归分析，从分析的11种方案中得到起点距为690m 和1 110m 的两条垂线组合的垂线平均流速与断面平均流速有较好的关系，适宜作为该站在线流量监测的代表性垂线。     

官良水文站水平式ADCP的流速率定分析

水平式ADCP技术应用的关键是指标流速与断面平均流速关系的率定[1],该文以官良站实测流量资料为基础,研究了水平式ADCP所测的指标流速与实测资料平均流速的相关关系,得出最佳的关系方程.通过水平式ADCP测得的指标流速代入率定方程,得出断面的平均流速,根据水位面积关系可得出现时水位对应的断面面积,平均流速与断面面积两者...     

长江防洪实体模型垂线流速相似性研究

根据实测资料 , 采用3点法、5 点法对比计算分析了原型和长江防洪实体模型的垂线平均流速两者间差异,同时比较分析原型与模型流速沿水深分布偏离程度。采用明渠对数流速公式探讨了模型变态后流速沿垂线分布的规律,在此基础上提出了长江防洪实体模型垂线平均流速与相对水深某位置处点流速的关系,观测资料分析表明,模型相对水深为 0.6 处的点水深处流速与垂线平均流速基本一致。     

宿松县大河水位流量关系变化原因分析

本文对宿松县大河河道整治后水位～流量关系和平均流速的变化情况进行了分析，找出了宿松县大河河道整治后水位～流量关系和平均流速的变化原因，说明了河道取沙对河道泄洪的影响，并提出了解决的办法。     

MODIFIED LOG-WAKE LAWS FOR TURBULENT FLOW OF THE OUTER AND INNER REGIONS IN SMOOTH PIPES

Based on theoretical analysis two modified log-wake laws for turbulent flow in smooth pipes are obtained,one is applicable to the outer region and other one to inner region,the new law for the outer region fits the velocity profile measured in smooth pipes by Zagarola very well and the effect of Reynolds number can be taken into consideration,the velocity profile for inner region satisfies the wall boundary conditions ,equals zero at the pipe wall and smoothly joins up with the velocity profile in outer region,the adopted eddy viscosity model is consistent with Laufer’s,Nunner’s and Reichardt’s experimental data.     

Fully rough submerged plane wall-jets

This study presents the turbulent flow field in submerged plane wall-jets on horizontal fully rough walls detected by a Vectrino velocimeter. For the comparison between the fully rough and smooth submerged wall-jets, the smooth submerged wall-jet case was also revisited. The two-dimensional Reynolds averaged boundary layer equations of a steady turbulent flow are analyzed to determine the velocity and Reynolds shear stress profiles in the fully developed zone of smooth and fully rough submerged wall-jets. The response of the turbulent flow characteristics in submerged wall-jets to wall roughness is examined from the point of view of similarity characteristics, growth of the length scale, and decay of the velocity and turbulence characteristics scales; and compared with the response of those to smooth and transitionally rough walls. The significant observation is that with an appropriate scaling, the velocity, Reynolds shear stress and turbulence intensities in the fully developed zone of fully rough submerged wall-jets are reasonably similar. The rate of decay of jet-velocity on fully rough walls is greater than that on smooth wall, but it is less than that on transitionally rough walls due to the presence of roughness sub-layer on the fully rough walls. Analysis of the third-order moments of velocity fluctuations reveals that the jet-layer is associated with the arrival of low-speed fluid parcel causing an effect of retardation; while the inner-layer of circulatory flow is associated with the arrival of high-speed fluid parcel causing an effect of acceleration. Wall roughness influences the peak values (both positive and negative) of the third-order moments increasing them significantly. Thus, on fully rough walls, the arrival processes of low- and high-speed fluid parcels become stronger in the jet-layer and the inner-layer of circulatory flow, respectively. Also, the peak values of streamwise and vertical flux of turbulent kinetic energy increase significantly in the presence of fully rough walls.     

NUMERICAL STUDY ON TURBULENT COUNTER-GRADIENT-TRANSPORT PHENOMENA IN ASYMMETRIC TURBULENT CHANNEL FLOW

1 .　BRIEFINTRODUCTIONTOCGTPHENOME NAINTURBULENCETurbulence ,prevalentinnature ,isofgreatimportanceinengineeringprojects .Asathree di mensionalunsteadynonlinearrandommotion ,oneofbasiccharacteristicsofturbulentflowisitsstrongerdiffusingeffectthanlaminarflow ,bywhichtheotherturbulentcharacteristicsaredeter mined .AccordingtoFourier’stheory ,turbulenttransportiscommonlyinthesamedirectionasgra dient .However ,thereareCGTphenomenaoccur ringincertainregionsofcomplexflows ,suchas…     

人工加糙对明渠紊动特性影响的试验研究

利用激光测速仪，对光滑壁面及人工加糙的明渠紊流进行了试验，测量了光滑壁面、水力过渡面、水力粗糙面不同水深情况下明渠紊流的纵向时均流速及脉动流速。通过实测资料分析了人工加糙对明渠紊流紊动强度的影响，得到了光滑面、过渡面及粗糙面紊动强度的发展变化规律。     

EXPERIMENTAL STUDY OF FLOW STRUCTURE BEHIND A CIRCULAR CYLINDER WITH WAVY SURFACE BY PIV

1. INTRODUCTIONThe flow around a s mooth circular cylinderhas been extensively studied by many researchers ,as can be seen fromthe comprehensive reviews ofWilliamson[1]and Rockwell[2]. Wang et al .[3]in-vestigated the 3D flow structure behind a circularcy…     

明渠自掺气水流掺气浓度分布Wood模型的改进研究

本文对明渠自掺气水流均匀流区掺气浓度分布的Wood计算模型建立中的两条基本假设进行了改进,在考虑掺气水流水气二相间相互作用的条件下,建立了气泡上浮速度和紊动扩散系数的计算式,并运用紊动扩散方程,导出了掺气均匀流掺气浓度分布的计算公式。计算值与实测值吻合良好。     

含柔性植物明渠水流阻力特性试验研究

利用水槽试验研究了无草、淹没型、非淹没型柔性植物水流阻力特性的变化规律,分析了含植物明渠沿程水面比降和阻力系数的变化特性。得到各植物阻力系数变化与尼库拉兹曲线基本相似,紊流范围内同样可划分为紊流光滑区、紊流过渡区、紊流粗糙区;探讨了各植物明渠等效河床的问题,据此确定了各植物的粗糙度,对植物粗糙度、水流雷诺数和阻力系数之间的关系进行了分析,并通过对各植物水流阻力系数的分区回归计算,得到各植物水流阻力的分区经验表达式,该方法能较好地应用于含植物明渠水流阻力系数的推求。     

冲积河流的水流挟沙能力

在前人研究成果的基础上分析了水流挟沙的物理模式，以挟沙水流紊动能量方程为理论基础，得出了紊动能产生项和粘性耗散项的表达式，由此推导出适用于水流的紊流三区(光滑区、过渡区和粗糙区)的挟沙能力计算式，依据天然河流实测资料和室内水槽试验资料，验证了该水流挟沙能力计算式．针对该计算式分析了影响水流挟沙能力的因素．     

Turbulent flow in a machine honed rough pipe for large Reynolds numbers: General roughness scaling laws

An alternate inner wall variable, for flow over a transitional rough pipe surface, is defined as the ratio of normal coordinate measured above the mean roughness level to the wall roughness scale. The Reynolds equations for mean turbulent flow in a transitional rough pipe, in two layers (inner and outer) are considered. The predictions of the mean velocity and friction factor in fully developed turbulent flow in a rough pipe flow, presented here, covers all types of roughness. The data for a particular case of the machine honed Princeton superpipe roughness, analogous to inflectional type roughness of Nikuradse, is presented, as two expressions using our roughness scale. The velocity profile and friction factor, on a transitional rough wall, are shown to be governed by the new log laws, which are explicitly independent of the transitional wall roughness. Further, the inflectional roughness has also been connected with geometric roughness parameters; like, arithmetic mean roughness, mean peak to valley heights roughness, root mean square (rms), roughness based on texture measure; and the friction factor implicit and approximate explicit formulas have also been proposed. In entire transition region between fully smooth and fully rough wall, monotonic roughness of Colebrook (Moody Chart) over estimaton the friction factor when compared with present inlectional roughness.     

NUMERICAL SOLUTION FOR TURBULENT FLOWS ON CONCAVE SURFACES OF SPILLWAY DAMS

1.INTRODUCTIONInthenumericalsolutionofturbulentflows,numerousturbulencemodelshavedemonstratedavarietyofgoodnumericalpredictionsbothqualitativelyandquantitatively.Amongthem,thek--smodelisthemostwidelyemployedisotropictwo--equationmodel.Ithasbeenextensivelyappliedtodifferentturbulentflowproblems.However,thestandardk--Emodelappearstobeinsufficientinpredictingthecomplexturblentshearlayers,suchasflowssubjectedtocurvatureandrotation.Thesensitivityofturbulentflowcharacteristicstoevensmallamount…