从东西关水电站高质量高速度施工看加快大,中型水电站建设速度

位于四川省武胜县嘉陵江中游的四川华能东西在水电工程，虽属中型电站，却具有大型工程的规模，工期短，强度高，难度大，施工条件差，在施工过程中，由于施工单位做到了“四个坚持”，即：坚持改革，强化管理，坚持项目施工，坚持均衡生产，文明施工；坚持优化施工组织设计，采用先进技术，先进工艺，从而有效地加快了工程建设。从一期截流到首台机组并网发电仅用了３３个月时间，建设速度快，施工质量好，工程效益和社会效益显著，     

高职院校提高体育教学成绩对比分析

文章结合高职院校体育教学实践,对提高跑步成绩进行了分析比较。     

轴对称面元上分布奇点在无界域中的诱导速度势和诱导速度

本文给出分布在轴对称面元上的奇点在无界域中的诱导速度势和诱导速度计算公式,奇点分布强度在轴向和径向采用高斯分点离散,周向采用富氏级数离散。用这种离散方法计算轴对称面元上分布奇点的诱导势和诱导速度,提高了计算效率和精度,可供用边界元方法求解势流问题时参考。     

乌江渡水电站扩机开挖爆破振动监控与研究

为确保乌江渡水电站原有的各项建筑物和发电设备以及扩机工程有关建筑物的安全运行，必须在乌江渡水电站扩机工程施工过程中对关键部位开挖所产生的爆破振动影响实施全面而有效的实时爆破监控。并根据监控成果的研究，指导开挖爆破作业。     

微滤技术及其在废水处理中的应用

在简要叙述微滤的分离原理、微滤及微滤膜的主要特点的基础上，重点综述微滤技术在处理二级生物处理出水，微污染水源水，含油废水，重金属、印染、造纸废水等各种废水中的应用。     

轴对称面元上分布奇点在无界域中的诱导速度热和诱导…

本文给出分布在轴对称面元上的奇点在元界域中的诱导速度热和诱导速度计算公式，奇点分布强度在轴向和径向采用高斯分点离散，周向采用富氏级数离散。用这种离散方法计算轴对称面元上分布奇点的诱导热和诱导速度，提高了计算效率和精度，可供用边界元方法求解热流问题时参考。     

三维粒子示踪测速技术的开发及初步应用

开发的单颗粒三维运动轨迹测量系统的硬件由四部摄像机、一台PC机和内置的图像卡组成。软件系统包括4路图像实时同步采集、图像二值化和聚合程序，坐标校正和转换，以及各统计参数的计算公式。系统标定的空间误差小于0.3mm，速度误差约为1.0mm/s。开发的颗粒三维运动测量系统在测量颗粒运动更长的轨迹、实现较高的采样频率和保证每个摄像机的高分辨率、只进行一次标定而进行各种水力坡度的试验及实现极大样本的采集等方面都取得了明显的进展，为研究颗粒运动的基本规律提供了新的方法。试验可以得出颗粒三维运动的瞬时速度，初步试验得出颗粒的纵向平均速度遵循对数分布，颗粒速度小于相应水流的运动速度。     

介绍一种新型节水灌溉技术——十八盘微集水

十八盘微集水灌溉分两种形式：一种暗蓄水的称水窑微集水；另一种明蓄水的称水窖微集水。水赛与农村的一般窑洞相类似，即在山坡上的崖头处（多选在上坎处）开挖一个水平洞，窑深和容积根据水源情况、灌区面积大小和供水人口多少及开挖难易程度等因素综合确定。做法是把进口用浆砌块石或砌砖抹面封严，把窑底和四壁用防渗材料（一般为水泥砂浆粉饰好）。水窑的一侧上部（一般为里侧）留有进水口，进水口外设沉淀地和过虑网，沉淀池上游挖截水沟或截水堰，依靠截水沟或截水堰拦引坡面雨水和山涧小溪至窑内蓄积起来。水赛的另一侧下部（一般为…     

网栅后湍流流动的LDV测量

本文应用ＬＤＶ技术对方管内网栅所形成的湍流流动做了详细测量，获得了管内不同位置湍流流动沿流动方向的衰减规律及网栅后不同距离处方管各断面上的速度及脉动速度分布情况。     

微絮凝-超滤组合工艺处理微污染原水的试验研究

对微污染水源水采用微絮凝-超滤组合工艺进行中试研究,结果表明,组合工艺出水水质稳定,对浊度、COD_(Mn)、UV_(254)、>2 μm颗粒物和原生微生物的去除都有很好的效果,去除率分别高达99.8%、48.5%、73.4%、99.9%和99.9%.     

DRAG REDUCTION IN A TURBULENT CHANNEL FLOW WITH HYDRO- PHOBIC WALL

This paper investigates a theoretical prediction of friction drag reduction in turbulent channel flow which is achieved by using superhydrophobic surfaces. The effect of the hydrophobic surface is considered to be a slip boundary condition on the wall, and this new boundary condition is added to Large Eddy Simulation (LES) equations. The predicted drag reduction at Reτ=180 is approximately 30%, which concurs with results obtained from Direct Numerical Simulation (DNS). An important implication of the present finding is that the near-wall turbulence structures are modified with streamwise slip velocity. In addition, a noticeable effect on the turbulence structure occurs when the slip length is greater than a certain value.     

Lattice Boltzmann simulation of solute transport in a single rough fracture

In this study, the lattice Boltzmann method （LBM） was used to simulate the solute transport in a single rough fracture. The self-affine rough fracture wall was generated with the successive random addition method. The ability of the developed LBM to simulate the solute transport was validated by Taylor dispersion. The effect of fluid velocity on the solute transport in a single rough fracture was investigated using the LBM. The breakthrough curves （BTCs） for continuous injection sources in rough fractures were analyzed and discussed with different Reynolds numbers （Re）. The results show that the rough frac~＇e wall leads to a large fluid velocity gradient across the aperture. Consequently, there is a broad distribution of the immobile region along the rough fracture wall. This distribution of the immobile region is very sensitive to the Re and fracture geometry, and the immobile region is enlarged with the increase of Re and roughness. The concentration of the solute front in the mobile region increases with the Re. Furthermore, the Re and roughness have significant effects on BTCs, and the slow solute molecule exchange between the mobile and immobile regions results in a long breakthrough tail for the rough fracture. This study also demonstrates that the developed LBM can be effective in studying the solute transport in a rough fracture.     

Analysis of shear rate effects on drag reduction in turbulent channel flow with superhydrophobic wall

We examined the shear rate effect on drag reduction of superhydrophobic surfaces with different slip lengths. For this purpose, turbulent channel flow was considered at the friction Reynolds numbers of Reτ = 180, 395, 500. By using Navier＇s slip condition it is shown that increasing shear rate leads to the greater reduction in drag force and also more reduction occurs in larger slip length. Based on the results, more than 25% drag reduction happens at a friction Reynolds number of Reτ= 500 for slip length of 1 ×10 5 m. The simulation results suggest that reduction in drag force occurs because slip condition reduces the Reynolds stresses, also weakens vorticity filed and the near-wall coherent structures, and therefore turbulence production is decreased.     

SLIP VELOCITY MODEL OF POROUS WALLS ABSORBED BY HYDROPHOBIC NANOPARTICLES SiO2

According to new slip effects on nanopatterned interfaces,the mechanism of enhancing water injection into hydrophobic nanomaterial SiO2 was proposed. When Hydrophobic Nanoparticles(HNPs)are adsorbed on surfaces of porous walls,hydrophobic nanoparticles layers are formed instead of hydrated layer, and slip effects appear on the pore wall when a driving pressure is applied to the rock cores sample. It makes fluid to move more quickly and the flow capacity increases greatly. Experiments on changing wettability of porous walls were conducted, and the phenomenon that porous walls surfaces were adsorbed by nanoparticles was validated with the Environment Scan Electron Microscopy(ESEM). The results of displacement experiments show that flowing resistance is greatly reduced , and water-phase effective permeability is increased by 47 % averagely after being treated by nanofluid. These results indicate that the slip effect may occur on nanoparticle film of porous walls. Based on this new mechanism of enhancing water injection about hydrophobic nanomaterial SiO2,a slip velocity model in uniform porous media was introduced, and some formulas for the ratio of slip length to radius, slip length ,stream slip velocity and flux increment were deduced. and calculated results indicate that the ratio of slip length to radius is about 3.54%-6.97%, and the slip length is about 0.024μm -0.063μm. The proposed model can give a good interpretation for the mechanisms of enhancing water injection with the HNPs.     

EXPERIMENTAL STUDY OF FRICTION FACTOR FOR GROUNDWATER FLOW IN A SINGLE ROUGH FRACTURE

To study the relationships between the friction factor f and the flow type in a single rough fracture, the formulae of f for both unconfined and confined flows are deduced based on previous studies. The relationships between f and the Reynolds number (Re) for different relative roughnesses are investigated experimentally. The Moody-type diagram, based on the deduced formula of f, is also plotted and the hydraulic characteristics of the flow in a rough fracture are analyzed. Results show that the Moody-type diagram of the experiment has a similar distribution to that of the conventional Moody diagram. It is found that the value of f in the experiment is much smaller than that of the conventional Moody diagram and turbulent flow appears easier for rough fractures, which can be explained by the separation phenomenon in boundary layers. The critical Re ranging from 650 to 700 in rough fractures is concluded based on the experimental results. It also can be concluded that the friction factor f is related not only with the Re and the relative roughness but also with the absolute roughness.     

Theoretical analysis of slip flow on a rotating cone with viscous dissipation effects

This paper is concerned with the mutual effects of viscous dissipation and slip effects on a rotating vertical cone in a viscous fluid. Similarity solutions for rotating cone with wall temperature boundary conditions provides a system of nonlinear ordinary differential equations which have been treated by optimal homotopy analysis method(OHAM). The obtained analytical results in comparison with the numerical ones show a noteworthy accuracy for a special case. Effects for the velocities and temperature are revealed graphically and the tabulated values of the surface shear stresses and the heat transfer rate are entered in tables. From the study it is seen that the slip parameter ? enhances the primary velocity while the secondary velocity reduces. Further it is observed that the heat transfer rate 1/2xNu Re? increases with Eckert number Ec and Prandtl number Pr.     

EXPERIMENTAL INVESTIGATION OF HYDRODYNAMIC CHARACTERISTICS OF OVERLAND FLOW WITH GEOCELL

The hydrodynamic characteristics of the overland flow with a geocell slope are different from those of traditional flows because of its special structure. In this paper,a hydraulic flume with different slope gradients is used to study the hydrodynamic characteristics of the overland flow with geocell. The differences of flow characteristics between the overland flow with the geocell slope and the traditional flows are studied, and the hydrodynamic characteristics are obtained, including the flow pattern, the flow velocity and the hydraulic friction factor for the slope flow with geocell under different flow rates and slope gradients. The results show that there is a positive power function relationship between the rill depth of the slope surface (h) and the drag coefficient of the Darcy Weisbach (f).There is a positive logarithmic function relationship between the drag coefficient f and the Reynolds number Red,and there is a negative power function relationship between the drag coefficient f and the Froude number Fr.     

Effects of Navier slip on unsteady flow of a reactive variable viscosity non-Newtonian fluid through a porous saturated medium with asymmetric convective boundary conditions

A study on the effects of Navier slip, in conjunction with other flow parameters, on unsteady flow of reactive variable viscosity third-grade fluid through a porous saturated medium with asymmetric convective boundary conditions is presented. The channel walls are assumed to be subjected to asymmetric convective heat exchange with the ambient, and exothermic chemical reactions take place within the flow system. The heat exchange with the ambient obeys Newton's law of cooling. The coupled equations, arising from the law of conservation of momentum and the first law of thermodynamics, then the derived system are nondimensionalised and solved using a semi-implicit finite difference scheme. The lower wall slip parameter is observed to increase the fluid velocity profiles, whereas the upper wall slip parameter retards them because of backflow at the upper channel wall. Heat production in the fluid is seen to increase with the slip parameters. The wall shear stress increases with the slip parameters while the wall heat transfer rate is largely unaltered by the lower wall slip parameter but marginally increased by the upper wall slip parameter.     

A hydrodynamics-based framework to evaluate the impact of fishways on drifting lake sturgeon larvae

Lake sturgeon (Acipenser fulvescens) have recently been a target for conservation in the Laurentian Great Lakes. While improving spawning success has been a major goal of these efforts, an often-overlooked component is the survival of the larvae after hatching, during the period of downstream drift. In a dammed river system, during this phase, larvae may need to drift past dam infrastructure. This journey past dams often results in an increase in larval mortality for a variety of reasons, including exposure to highly turbulent flow. Quantifying the aspects of turbulence related to larval mortality within fishways will inform retrofitting or future design efforts of fishways to improve larval viability. This study uses dimensional arguments to characterize the flow conditions influencing larval viability through fishways. One such condition discussed here is strain rate, which can be used as a diagnostic basis to determine candidate fishways for conservation measures. Based on Kolmogorov’s theory (1941), the strain rate present in the fishway at the pertinent scale for lake sturgeon larvae, S_η, can be estimated using the fishway’s macroscale Reynolds number Re, the relevant macroscale fishway velocity U, and the smallest fishway pool dimension l_e as S_ηl_e/U ≈ Re^1/2. This approach is illustrated in the case of the Vianney-Legendre Fishway in Québec, and determined this fishway to be potentially hazardous to drifting lake sturgeon larvae.     

微尺度流动界面现象及其流动边界条件分析

水平微尺度毛管中低Reynolds数流体流动出现许多另人费解的现象,如流动前缘并未出现Poiseuille速度剖面,而似一种“段塞式”流动,固/液界面看似不符合无滑移边界条件. 该文针对这些易引起困惑的问题,利用可视化微管流动实验及岩石孔隙仿真光刻模型流动实验,考察了润湿性对微尺度毛管中流体流动的影响,探讨了微尺度毛管中表面流动现象产生的实质.结果表明,在微尺度流动中观察到的小分子液体“段塞流动现象”,以及看似壁面滑移流动等现象,其实质是液/固壁面仍为无滑移边界,三相接触点以尤如运动的“坦克的链轨”发展方式,沿壁面发展,从而产生“段塞式”流动.虽然仍在低速层流的条件下,但由于界面张力的作用,接近动界面处流动质点的运动已不再保持一维直线运动.