故园情

置身于喧嚣的都市,眼里尽是灰色的楼群、飞驰的汽车、步履匆匆的行人,头顶是一线灰蒙蒙的天空,鼻孔里进出着污浊的空气,耳朵里充斥着无穷无尽的噪音,不由得使人常常想起家乡世外桃源般宁静的小山村.幽幽南山之下,四围山色之中,绿树掩映里,错落几户人家,潺潺溪水穿村而过,但闻鸡犬声,而无车马喧.家家养一两头牛羊,种两三亩薄田,务三四畦青菜,点四五架黄瓜.目之所及尽是青山绿水,两袖一甩,俱是明月清风.这就是我生于斯长于斯的家园.     

陈进副院长荣获湖北省环境保护政府奖

<正>2015年6月2日,在世界环境日来临之际,湖北省政府在洪山礼堂隆重召开大会表彰获得2015年"湖北省环境保护政府奖"的9个集体和6个个人,省政府、省人大和省政协领导共同为获奖集体和个人颁发了奖牌、奖章和证书。由长江水利委员会推荐,经湖北省环境保护政府奖评审委员会和环境奖评审领导小组先后评审、现场考察、审定和公示后,长江科学院副院长陈进获此殊荣。近10 a来,陈进副院长积极从事水资源及水环境保护科学普及工作,相关研究成果获得3项省部级以     

北京的母亲河上亟需实现"人水和谐"

1 永定河是北京的母亲河 1.1 北京城座落在永定河的洪积冲积扇上 洪荒时代,源自黄土高原的永定河,经过今天的山西、内蒙古、河北,咆哮而来,从上游携带的大量泥沙由于河道纵坡变缓而沉积.地势上西北高东南低,崇山峻岭从西北部缓缓倾斜,不断向东南延伸.燕山、太行山2条山脉在昌平南口的官沟交汇,形成一个向东南展开的状如围屏的弧形大山湾,地理学上称之为"北京湾".在其东南平原上,蜿蜒汇流着北京的5大水系:永定河、拒马河、温榆河、潮白河、泃河.其中以永定河最大,北京所在的平原就是在永定河洪积冲积扇的基础上形成的.从3000多a前的燕都蓟城,到852 a前的金中都城:从700多a前的元大都城到明清北京城,城址虽有所变迁,但都无一例外地建在永定河的洪积冲积扇上.     

抢险小水电贡献大作用——水利部抗震救灾阿坝工作组水电站抢险纪实

对于灾区人们来说,突如其来的强烈地震,是一段难以抹去的黑色记忆,他们凄迷的眼神,太多地渴盼光明和温暖.电--是他们重建家园的力量泉源.     

致深入抗震救灾第一线水利干部职工的慰问信

奋战在水利抗震救灾第一线的广大干部职工: 2008年5月12日14时28分,四川汶川发生了8.00级特大地震,给灾区人民的生命财产造成了巨大损失.在这场突如其来的地震灾害面前,广大水利干部职工与党中央、国务院和全国人民共同抗击,共克时艰.     

非大修期间对立式同步电动机油冷却器的漏水处理

1 基本情况 江苏省泗阳第一抽水站属于南水北调第四梯级站.该站装有TDTF-500/120-16/32立式同步电动机(可逆式)20台套.由于建站时间早,运行时间长,且冷却用水又常受到水质、水中微生物以及供水方式、压力等因素的影响,导致部分机组油冷却器水管产生不同程度的渗漏.而油冷却器水管一旦发生破裂漏水,特别是上油缸漏水,由于负压的存在,易产生虹吸现象,将油缸内的润滑油吸出,进而造成散热、润滑的中断,直至出现烧瓦.     

灾难降临我们感同身受——"5·12"四川汶川地震见闻

5月12日下午14时28分,正是中国三峡总公司成都基地相关部门职工上班时间.突然,大家都感觉到门窗哗哗作响,办公楼和公寓楼在剧烈震动,办公楼的天花板不断有物体下落,旋即停电,人们一片惊慌,纷纷跑出大楼.     

对构建和谐灌区建立减轻农民水费负担新机制的探讨

文章结合洛惠灌区近年来的工作经验,认为在社会主义市场经济深入发展的新形势下,"减负"必须遵循市场规律、价值规律,正确理解和区分农民合理负担和不合理负担,多管齐下,综合治理,既要有行政的手段,更要有法制的手段、经济的手段,大胆实践,建立科学的减负新机制,才能从根本上解决农民负担过重的问题.     

论述摘登

不要让民勤成为第二个罗布泊,这不仅仅是民勤一个地区的问题,更表达了国家改善生态环境的决心和意志. --中共中央政治局常委、国务院总理温家宝参加十一届全国人大一次会议甘肃代表团的审议时说     

山区梯田集成配套小型水工程的和谐性分析模型

针对山区梯田集成配套小型集引蓄排水工程的建设和运行使用,对因与工程区自然、人文社会经济环境不和谐,导致效益低下,土地、资金大量浪费,工程难以实现其期望价值等问题进行了分析.按工程与自然环境、人文社会相互耦合这一广义的复合系统观念,建立了一与梯田集成配套的小型水工程和谐性的分析模型,并在贵州毕节地区的实际工程中进行了应用.     

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…     

亚临界雷诺数下波浪型圆柱绕流的数值模拟及减阻研究

采用大涡模拟数值方法对亚临界雷诺数Re=3000下波浪型圆柱的绕流现象进行研究分析。研究结果表明,波浪型圆柱的三维尾迹涡结构能得到很好的控制,它在轴向方向呈现周期性正负涡的交替分布特性。随着幅值的增大,波浪型圆柱表面的自由剪切层得以延展,使得旋涡的脱落发生在波浪型圆柱下游较远处,从而达到减阻的目的。波浪型圆柱与普通直圆柱相比,其幅值对平均阻力系数及脉动升力系数的减少及尾迹控制有着更重要的影响,最大减阻可达16%。     

Flow characteristics of the two tandem wavy cylinders and drag reduction phenomenon

This paper presents an extensive numerical study of 3-D laminar flow around two wavy cylinders in the tandem arrangement for spacing ratios (L/Dm ) ranging from 1.5 to 5.5 at a low Reynolds number of 1...     

Large-eddy simulation of the flow past both finite and infinite circular cylinders at Re =3900

The flow past a finite circular cylinder with a height-to-diameter ratio of 1.5 and an infinite circular cylinder of the same diameter at a Reynolds number Re= 3 900 is investigated using the large eddy simulation(LES). The objective of the present study is to explore the differences of the flow mechanisms between the finite and infinite circular cylinders. It is shown that the free end of the finite circular cylinders affects the wake region significantly. The mean drag coefficient and the fluctuating lift coefficient of the finite circular cylinder are smaller than those of the infinite circular cylinder. The three-dimensional separation and the separated shear layer instability of the finite circular cylinder can obviously be observed. The existence of an arch vortex in the average flow downstream of the free end is demonstrated.     

2-D eddy resolving simulations of flow past a circular array of cylindrical plant stems

In the present study, 2-D large eddy simulations(LES) are conducted for flow past a porous circular array with a solid volume fraction(SVF) of 8.8%, 15.4% and 21.5%. Such simulations are relevant to understanding flow in natural streams and channels containing patches of emerged vegetation. In the simulations discussed in the paper, the porous cylinder of diameter D contains a variable number of identical solid circular cylinders(rigid plant stems) of diameter d= 0.048 D. Most of the simulations are conducted at a Reynolds number of 2 100 based on the diameter D and the velocity of the steady uniform incoming flow. Though in all cases wake billows are shed in the regions where the separated shear layers(SSLs) forming on the sides of the porous cylinder interact, the effect of these wake billows on the mean drag is different. While in the high SVF case(21.5%), the total drag force oscillates quasi-regularly in time, similar to the canonical case of a large solid cylinder, in the cases with a lower SVF the shedding of the wake billows takes place sufficiently far from the cylinder such that the unsteady component of the total drag force is negligible. The mean amplitude of the oscillations of the drag force on the individual cylinders is the largest in a streamwise band centered around the center of the porous cylinder, where the wake to wake interactions are the strongest. In all cases the maximum drag force on the individual cylinders is the largest for the cylinders directly exposed to the flow, but this force is always smaller than the one induced on a small isolated cylinder and the average magnitude of the force on the cylinders directly exposed to the flow decreases monotonically with the increase in the SVF. Predictions of the global drag coefficients, Strouhal numbers associated with the wake vortex shedding and individual forces on the cylinders in the array from the present LES are in very good agreement with those of 2-D direct numerical simulations conducted on finer meshes, which suggests LES is a better option to numerically investigate flow in channels containing canopy patches, given that LES is computationally much less expensive than DNS at high Reynolds number. To prove this point, the paper also discusses results of 2-D LES conducted at a much higher Reynolds number, where the near-wake flow is strongly turbulent. For the higher Reynolds number cases, where the influence of the turbulence model is important, the effect of the sub-grid scale model and the predictive capabilities of the unsteady Reynolds averaged Navier-Stokes(RANS) approach to predict flow past porous cylinders are discussed.     

The numerical and experimental investigations of the near wake behind a modified square stay-cable

The near wake structure, the wake-flow characteristics and the drag coefficients behind a modified square stay-cable(MSC) with sinusoidal variations of the cross-section area along the spanwise direction are investigated experimentally and numerically. The Reynolds numbers are chosen as 100 and 500 for the laminar flow and Re= 6 000 and 22 000 for the turbulent flow. The detailed near wake structures, the velocity fields and the force coefficients for the MSC are captured, the effect of the Reynolds number on the flow structure for the MSC is studied. The numerical and experimental investigations show that the free shear layers from the leading edge are widened and prolonged and then roll up into vortices further downstream the MSC, unlike a straight square stay-cable(SSC) under the same flow conditions. As a result, the distinct mean drag reduction and the fluctuating lift suppression are observed for all Reynolds numbers, a drag reduction of at least 15.8% and the rms lift coefficient reduction of up to 95% are observed, as compared with the case of a straight square stay-cable at Re= 500.     

近壁圆柱绕流的壁面积沙现象机理分析

针对近壁圆柱绕流过程中出现的在平板壁面积沙现象用数值模拟方法进行了机理分析。应用标准k-ε湍流模型和流函数-涡量法分析了不同间隙比（圆柱与壁面间的距离对圆柱直径之比）下的尾流特性，得到圆柱表面升阻力和平板壁面压强脉动。结合流动显示的染色粒子图方法，进行了详细的分析并提出近壁圆柱绕流过程中在圆柱下游平板壁面形成沙粒线的可能机理。     

低雷诺数下并列双波浪柱尾迹干扰效应数值模拟

该文针对雷诺数Re=100下不同波长参数(/mλD=2、4、6和8)、不同间距比(1.5/3.5m≤L D≤)的并列双波浪柱后尾迹复杂的三维流动结构及干扰效应进行了数值研究。研究表明:三维并列双波浪柱在较小的间距比/1.5mL D=时,波峰对波谷排列的并列波浪柱后尾迹呈现明显偏置双稳流动结构,而波峰对波峰排列工况下基本呈现单一波浪型钝体后尾迹流动结构(尤其是在大波长/mλD=6和8时);当间距比/3mL D≥时,随着波长/mλD的增大,上下波浪柱各自呈现单波浪柱后尾迹流动结构;较大波长的三维波浪形状更好地组织了后尾迹三维流动结构,减少了并列双波浪柱后尾迹的相互干扰,从而减阻减振明显,最高减阻可达14.5%,脉动升力系数上下游波浪柱均趋于0.1。该研究可为近海工程的多立管结构及悬索桥的拉索振动抑制等提供理论支持。     

CALCULATION OF VISCOUS FLOW AROUND CIRCULAR CYLINDER WITH THREE-DIMENSIONAL NUMERICAL SIMULATION

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｆｌｏｗａｒｏｕｎｄａｃｉｒｃｕｌａｒｃｙｌｉｎｄｅｒｉｓｖａｌｕａｂｌｅｉｎｏｉｌｃｏｍｐａｎｉｅｓｏｒｏｆｆｓｈｏｒｅｉｎｄｕｓｔｒｙｔｈａｔｒｅｌｙｉｎｍｏｓｔｃａｓｅｓｏｎｓｕｂｓｅａｐｉｐｅｌｉｎｅｏｒｒｉｓｅｒｓｔｏｔｒａｎｓｐｏｒｔｇａｓａｎｄｏｉｌｆｒｏｍｏｃｅａｎｇｒｏｕｎｄｓｔｏｌａｎｄｏｒｓｕｒｆａｃｅｐｌａｔｆｏｒｍ .Ｗｅｓｈｏｕｌｄｅｎｓｕｒｅｔｈａｔｔｈｅｓｅｏｆｆｓｈｏｒｅｓｔｒｕｃｔｕｒｅｓａｒｅｒｅｓｉｓ ｔａｎｔａｎｄｓｔａｂ…     

非淹没圆柱群局部水流场特征分析

本文基于带自由表面水动力学数值模型,采用双方程k-ω的剪切应力输运(SST)湍流模式,对非淹没刚性圆柱群水流场进行了三维数值模拟。通过与实验数据的对比分析,验证了模型的有效性及模拟精度。通过圆柱群绕流场特征的模拟分析,探究了不同圆柱雷诺数和固体体积分数对柱群内剪切层渗入长度(δ)、柱群后尾流区剪切层长度以及床面应力空间分布特征的影响。