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1.
双侧竖缝式鱼道水力特性研究   总被引:1,自引:0,他引:1  
研究分析不同水池长宽比条件下双侧竖缝式鱼道的水池流场结构及其水力学指标,为双侧竖缝式鱼道布置参数的优化选择提供技术依据。基于单侧竖缝式鱼道体型参数的研究成果,选取导板长度与水池宽度之比为0.25、竖缝宽度与水池宽度之比为0.15、导向角度为45°作为研究的基本体型;鱼道来流边界设置为压力进口,上游水深设置为2 m,出流边界设置为压力出口,下游水深设置为2 m;模型顶部设置为压力进口,进口压强为1.01×105Pa,边墙设置为固壁边界。采用三维数值模拟的方法研究分析了水池长宽比分别为4∶8、5∶8、5.5∶8、5.75∶8、6∶8、6.5∶8、7∶8、8∶8、9∶8的条件下双侧竖缝式鱼道的水池流场结构及其水力学指标。在不同水池长宽比条件下,鱼道常规水池内存在3种典型流场结构,其主流轨迹线、主流流速沿程衰减规律以及回流区分布等水力学指标均有不同,典型长宽比取值区间分别为4∶8~5.5∶8、5.75∶8~6.5∶8及7∶8~9∶8;对比发现,长宽比在5.75∶8~6.5∶8区间范围时,主流区宽度相对较大,水池空间利用较为充分,沿程流速衰减情况也较好,回流区主要分布于主流两侧且大小适中。初步认为长宽比5.75∶8~6.5∶8的水池流场结构较为合理。  相似文献   

2.
在23±0.5℃水温条件下,利用游泳行为测试水槽分析早期发育阶段鳙幼鱼(Hypophthalmichthys nobilis)(5.0~9.0cm,2.5~11.5g)游泳行为特性与水流流速变化的响应关系。结果表明该体长范围鳙幼鱼的平均临界游泳速度为0.468±0.161m/s;平均突进游泳速度为0.672±0.154m/s,且绝对临界游泳速度和绝对突进游泳速度均随体长的增加而线性增加,相对突进游泳速度随体长的增加而线性减小;绝对突进游泳速度与绝对临界游泳速度存在如下关系: ;在测试突进游泳速度中鱼类游泳行为随水流流速变化存在4种游泳状态相互穿插(顶流前进、顶流后退、顶流静止、顺流而下),根据鱼类运动过程中的四个阶段分别对应的4种游泳状态,得到以鳙幼鱼为过鱼对象的鱼道池室主流流速为16.0~46.5cm/s;对于鱼道高流速区的竖缝、孔口等最佳流速应为46.5~85.4cm/s。本研究成果补充了四大家鱼游泳特性指标,为四大家鱼资源保护、鱼类洄游通道建设提供参考依据。  相似文献   

3.
常规鱼道的研究和设计大多侧重于其内部结构和水流条件等方面,对鱼道进口位置布置及结构优化的研究相对较少,往往存在鱼类发现并进入鱼道较为困难的情况。通过建立鱼道进口设计的生态水力学指标,提出了某项目集诱鱼进口所需要满足的流速范围为0.47~1.30 m/s,将鱼类游泳能力与鱼道进口流态指标相结合,用标准三维κ-ε模型数值模拟的方式,对以往鱼道进口位置的选择原则进行了验证,提出了一种可控流量、流速的新型诱鱼补水装置,对鱼道进口结构进行优化。该诱鱼补水装置利用局部水流落差,上游发电下泄水流进行诱鱼补水,避免采用自库区压力管道引水而产生的消能问题,降低了鱼道运行的成本;同时降低机组满发或发电流量较高时河段内的流速,可达到灵活调控诱鱼水流进而诱导鱼类进入鱼道完成洄游的效果,最终完成鱼道进口的优化,提高过鱼效果。  相似文献   

4.
受枢纽布置与地形地质条件影响,竖缝式鱼道穿越公路、桥梁等建筑物或实现大转弯时通常需要布置90°转弯段。根据导板的布置位置,90°转弯段分为内内型、内外型、外内型与外外型4种类型。采用数值模拟技术计算4种类型90°转弯段的水流流场,主流区水流均紧贴边墙流动,主流区两侧出现尺度过大的回流区。针对出现的不利流态,提出了以增设整流导板的方式调整水流结构,并对水流结构改进后的水力特性进行了对比研究。增设整流导板后,主流区大致居中,主流衰减效果显著;回流区尺度合理,回流流速甚小。内外型90°转弯段增设一整流导板后,yi/B值介于0.30~0.71,说明主流区主要位于转弯段中间40%区域内;主流区两侧主要分布着3个回流区,位于弯段与弯段下游回流区的尺度最大,影响域为常规水池面积的0.9倍,长宽比为3.25,说明大尺度回流区的影响域为椭圆形区域,可便于鱼类游入与游出;弯段与弯段下游回流区内,靠近边墙的最大流速不超过竖缝断面平均流速的0.23倍,中心流速甚小,有利于鱼类良好休憩。内外型90°转弯段水流结构改进效果较其他3种类型更为明显,在实际工程中可考虑优先采用。  相似文献   

5.
鱼道是解决拦河筑坝阻隔鱼类洄游的重要手段之一。为了满足兴建峡江水利枢纽工程后洄游鱼类上溯的要求,保护赣江水生生态环境的完整性,减缓工程对鱼类种群遗传交流的影响,针对峡江水利枢纽实际情况制定了鱼道过鱼方式。鱼道采用垂直竖缝式结构设计,由上游鱼道(出口段)、坝体过鱼孔口、下游主、副鱼道(进口段)、集鱼系统及连接段组成,设计主要过鱼季节为4—7月,流速0.7~1.2 m/s。采用仪器监测与人工观察相结合的方式对峡江鱼道过鱼效果进行了初步监测。监测结果显示:2017年监测到过鱼总数67.8万尾,其中上行占41.67%;期间共监测到22种鱼类,共计4目、7科、18属,以小型鱼类为主,如贝氏■(Hemiculter bleekeri)、三角鲂(Megalobrama terminalis)、银鲴(Xenocypris argentea)、银鮈(Squalidus argentatus);不同季节过鱼数量不同,其中以二季度最多,占总数49.17%,过鱼数量以7月最多;过鱼数量昼夜差别大,以上午10:00至下午16:00是过鱼数量最多;与国内其他鱼道相比,峡江鱼道过鱼数量较多,过鱼效果显著。  相似文献   

6.
为了探究斑重唇鱼的游泳能力,给过鱼设施设计和鱼类游泳行为学研究提供基础参数,本研究以木扎提河野生斑重唇鱼(全长TL=12~16 cm)为研究对象,测定了其在(16.6±1.6)℃水温下的感应流速、临界游泳速度、爆发游泳速度及持续与耐久游泳能力。结果显示,斑重唇鱼感应流速为(0.18±0.02)m/s,相对感应流速为(1.40±0.23) BL/s (BL为体长);临界游泳速度为(1.02±0.15) m/s,相对临界游泳速度为(8.58±1.65) BL/s;爆发游泳速度为(1.39±0.17) m/s,相对爆发游泳速度为(10.92±1.86) BL/s;最大持续游泳速度为0.87 m/s,最大耐久游泳速度为1.37 m/s,与平均爆发游泳速度相近。其持续游泳时间与流速呈负相关(l g T=?5:136X+8:504)。当以斑重唇鱼为主要过鱼对象时,建议为吸引鱼类进入鱼道,进口流速设计为1.02~1.39 m/s,休息池主流设计为0.20~1.02 m/s,鱼道竖缝处流速宜低于0.85 m/s。鱼道长度为1 000 m时,鱼道内平均水流速度应低于0.78m/s。本研究结果可为新疆木扎提河流域鱼类游泳能力研究提供参考,对保护日益减少的鱼类资源具有重要意义。  相似文献   

7.
应用于鱼道设计的新疆木扎提河斑重唇鱼的游泳能力测试   总被引:1,自引:0,他引:1  
为了探究斑重唇鱼的游泳能力,给过鱼设施设计和鱼类游泳行为学研究提供基础参数,本研究以木扎提河野生斑重唇鱼(全长TL=12~16 cm)为研究对象,测定了其在(16.6±1.6) ℃水温下的感应流速、临界游泳速度、爆发游泳速度及持续与耐久游泳能力。结果显示,斑重唇鱼感应流速为(0.18±0.02)m/s,相对感应流速为(1.40±0.23) BL/s (BL为体长);临界游泳速度为(1.02±0.15) m/s,相对临界游泳速度为(8.58±1.65) BL/s;爆发游泳速度为(1.39±0.17) m/s,相对爆发游泳速度为(10.92±1.86) BL/s;最大持续游泳速度为0.87 m/s,最大耐久游泳速度为1.37 m/s,与平均爆发游泳速度相近。其持续游泳时间与流速呈负相关(${\rm lg}T = - 5.136{{X}} + 8.504$)。当以斑重唇鱼为主要过鱼对象时,建议为吸引鱼类进入鱼道,进口流速设计为1.02~1.39 m/s,休息池主流设计为0.20~1.02 m/s,鱼道竖缝处流速宜低于0.85 m/s。鱼道长度为1 000 m时,鱼道内平均水流速度应低于0.78 m/s。本研究结果可为新疆木扎提河流域鱼类游泳能力研究提供参考,对保护日益减少的鱼类资源具有重要意义。  相似文献   

8.
洄游通道的连通性及其水文条件,是制约鱼类正常洄游和产卵繁殖的关键因素,现有的生态流量相关研究更多侧重于产卵场栖息地模拟,忽略了鱼类洄游水流条件的重要性。为了探究流速条件对鱼类洄游上溯的影响,选取体长(55±5)cm的草鱼(Ctenopharyngodon idellus)为实验对象,通过搭建鱼类洄游仿真河道,营造不同的流速工况,观察不同情景方案下实验鱼群上溯洄游情况,并利用模糊逻辑法对鱼类上溯洄游率、平均上溯时间及上溯持续性等实验参数进行综合分析,探索草鱼洄游的适宜流速条件与适应阈值。结果显示,在流速0.20m/s以下时,草鱼基本无上溯行为;流速0.25~0.80m/s,70%样本在15min内完成上溯,但0.25~0.30m/s时,鱼群上溯缺乏明显的持续性;0.90~1.00m/s时,80%以上样本在5min快速完成上溯;流速超过1.1m/s时,上溯成功率明显降低。研究表明,实验草鱼洄游的适宜流速范围是0.40~1.00m/s,而刺激草鱼洄游的最小流速阈值是0.20m/s。相关结果可为河流生态水力学模拟和河流生态修复以及水利工程生态调度提供技术支撑。  相似文献   

9.
为了解鱼在复杂水流环境中的运动行为,提升鱼道过鱼效果,实验通过在水槽中放置障碍物,分析不同来流速度(1,3和5 BL/s)(BL/s即体长每秒)下鲢幼鱼顶流静止和顶流前进时的游泳动力学表现,提取的游泳动力学指标有摆尾频率、摆尾幅度、对地游泳速度、游泳加速度和运动步长。结果发现,半流速度1 BL/s下,与自由来流相比,鲢幼鱼在障碍物后方顶流静止时,摆尾频率降低,摆尾幅度增加;顶流前进时,摆尾频率、对地游泳速度、游泳加速度和运动步长降低,摆尾幅度增加。半流速度3 BL/s下,障碍物有助于节省鱼类运动能量的消耗。在有障碍物的水流中,顶流静止时的摆尾频率随流速的增加而增加;顶流前进时,摆尾频率、摆尾幅度和游泳加速度随流速增大而增大,而运动步长随流速增大而减小。位置偏好研究表明,当流速为3 BL/s时,鲢幼鱼明显集中在距离障碍物后方约5~30 cm处游动,停留时间占比达92.5%,可能采用了卡门步态的运动模式;当流速为1和5 BL/s时,鲢幼鱼没有表现出非常明显的位置偏好;在自由来流中,鲢常贴壁游泳,亦没有明显的位置偏好,表明障碍物和流速的结合可为鱼类提供水流藏匿场,研究结果为鱼道设计提供重要参考依据。  相似文献   

10.
为检验流溪河水厂坝建立的丹尼尔式鱼道试点工程效果,在2015-2016年鱼道主要过鱼时段4-10月,利用张网法逐日监测。结果显示,鱼道取样共采集鱼类906尾,隶属于3目、8科、32属、34种,体长范围5~74cm,优势种为尼罗罗非鱼(Tilapia niloticus)(数量比51.10%)、歺又鱼(Hemiculter leucisculus)(16.23%)、唇鱼骨(Hemibarbus labeo)(8.17%)、银鮈(Squalidus argentatus)(6.73%)、东方墨头鱼(Garra orientalis)(1.55%),以定居型鱼类为主,未见河口洄游性鱼类。水温与上游水位是影响鱼类种类时间分布的主要环境因素。聚类分析表明,6月过鱼群体的种类和数量独成一类,与其他月份鱼类群体最不相似。虽然Shannon多样性指数在5月和6月分别为2.068和1.719,但总体偏低(1.451±0.535),而Margalef丰富度指数差别较小,表明不同鱼类对鱼道入口的感应存在种间差异,推测是由工程全段翻滚闸门下泄水流导致鱼道入口不易发现所致。研究表明,丹尼尔式鱼道试点工程效果较好,为该河段的绝大部分鱼类提供了上溯通道,对流溪河构建整体过鱼设施体系起到了良好的示范作用,有助于流溪河生态系统的健康与恢复。  相似文献   

11.
The effectiveness of a vertical-slot fishway on the Burnett River barrage for facilitating migration of fish was assessed. In 100 samples taken at the top and bottom of the fishway, over 52 000 fish representing 34 species were collected at a maximum rate of 4500 fish per day. In contrast, less than 2000 fish ascended the original pool-and-weir fishway in 128, 24 h samples at the top between 1984 and 1987. Juvenile size classes dominated the abundance of many species in the present study and fish between 24 and 930 mm in length ascended the vertical-slot fishway. However, passage of small fish was restricted and for new fishways on tidal barriers a further reduction in head loss between pools is recommended. Importantly, the width of the vertical-slots was too small for effective upstream passage of large Queensland lungfish, Neoceratodus forsteri (Krefft). The greatest diversity of fish species was found during low river flows. The findings suggest that vertical-slot fishways with wide pools and low turbulence pass a diverse range of fish fauna present in subtropical coastal rivers.  相似文献   

12.
In an attempt to restore the connectivity of fragmented river habitats, a variety of passage facilities have been installed at river barriers. Despite the cost of building these structures, there has been no quantitative evaluation of their overall success at restoring fish passage. We reviewed articles from 1960 to 2011, extracted data from 65 papers on fish passage efficiency, size and species of fish, and fishway characteristics to determine the best predictors of fishway efficiency. Because data were scarce for fishes other than salmonids (order Salmoniformes), we combined data for all non‐salmonids for our analysis. On average, downstream passage efficiency was 68.5%, slightly higher than upstream passage efficiency of 41.7%, and neither differed across the geographical regions of study. Salmonids were more successful than non‐salmonids in passing upstream (61.7 vs. 21.1%) and downstream (74.6 vs. 39.6%) through fish passage facilities. Passage efficiency differed significantly between types of fishways; pool and weir, pool and slot and natural fishways had the highest efficiencies, whereas Denil and fish locks/elevators had the lowest. Upstream passage efficiency decreased significantly with fishway slope, but increased with fishway length, and water velocity. An information‐theoretic analysis indicated that the best predictors of fish passage efficiency were order of fish (i.e. salmonids > non‐salmonids), type of fishway and length of fishway. Overall, the low efficiency of passage facilities indicated that most need to be improved to sufficiently mitigate habitat fragmentation for the complete fish community across a range of environmental conditions.  相似文献   

13.
The swimming capabilities of adult Pacific lamprey, Entosphenus tridentatus Gairdner, were tested in an experimental vertical‐slot fishway in response to three different fishway features: water velocity (1.2, 1.8 and 2.4 m s?1), the length of the vertical slot (0.33, 0.66, 1.00 m) and during the presence/absence of a turbulence‐intensifying structure that increased turbulence for each respective treatment. Passage success was lowest (52.7%) and attachment rates were highest (92.9%) during the most difficult passage conditions (high velocity, high turbulence, long slot length). Passage success was >83% for all other treatment combinations. Although passage of the vertical‐slot weir was not associated with fish body size, Pacific lamprey with larger dorsal distances (distance between the two dorsal fins) were more likely to pass the vertical‐slot weir. Increased attachment rates and longer attachment times during strenuous passage conditions suggest that endurance capacity may be an important factor limiting the passage of Pacific lamprey at fishway obstacles.  相似文献   

14.
Abstract An experimental fishway was used to examine adult Pacific lamprey, Lampetra tridentata (Gairdner), behaviour in a series of attraction and passage‐performance tests. Among all experiments, lamprey oriented to the fishway floor and walls and were attracted to both ambient and concentrated flow. When confronted with high‐velocity areas (vertical‐slot and submerged‐orifice weirs), many lamprey failed to pass upstream. However, lamprey were able to find and take advantage of low‐velocity refuges when they were provided. Lamprey climbed shallow‐ and steep‐angled ramps when attraction cues were sufficient and other passage routes were restricted. The combined results demonstrated the passage challenges that fishways designed and operated for salmonids present to non‐salmonid species. They also highlight the importance of evaluating trade‐offs between fishway attraction and passage efficiency. The experiments were integrated with tagging studies and development of lamprey‐specific passage structures, a research combination that provided an effective template for fishway performance evaluations.  相似文献   

15.
Fishway entrance modifications enhance fish attraction   总被引:1,自引:0,他引:1  
Two Denil fishways on the Grand River, Ontario, were monitored annually since 1994 for activity by several dozen fish species. Fishway entrances were enlarged and repositioned approximately 2 m closer to the weir face, in areas where fish were attracted by weir discharge. These simple modifications resulted in increased attraction efficiency for pumpkinseed, Lepomis gibbosus (L.). After modifications, annual relative rate of recapture was 39% (95% confidence interval [CI]=32–46%), representing a 2.6–3-fold increase in fishway use relative to pre-modification conditions. Median daily recapture rates also increased significantly from 0% at both fishways to approximately 2%. These results suggest that fishway entrances should be located as close to a dam or weir face as possible, but velocity barriers from spillway or tailrace discharge must not compromise access.  相似文献   

16.
Computational fluid dynamics (CFD) software was used to construct two-dimensional axisymmetric simulations of the turbulent flow inside 1.5, 5, 9.15 and 10 m tanks containing rotating water. The water rotation was induced mathematically by either placing a rotating cover on the surface of the water or locating a tangential water inlet near the top of the side wall. Central and side drains evacuated the water from the tank when using an inlet. The rotating cover produced a forced vortex in the tanks similar to the one observed in actual rearing tanks when the majority of the flow is leaving via the side drain. The predicted flow structure in tanks with an inlet can be divided into three regions: a narrow region along the side wall where the rotating water is moving down toward the floor, a thin boundary layer along the floor where the rotating water is moving radially inward, and a large region in the bulk of the tank where radial and axial velocities are small and the tangential velocity is independent of elevation but varies with radial position. Calculations were performed with the k-ε (RNG) and Reynolds stress turbulence models. Converged solutions were easier to obtain with the k-ε (RNG) model but only the Reynolds stress model could predict the strong vortex which is experimentally observed to form in the central portion of the tank as the flow leaving via the center drains is increased. The simulations predict that the thickness of the floor boundary layer is proportional to the tank diameter and that the radial velocity within the floor boundary layer is maximum at an elevation equal to about 10% of the boundary layer thickness. At any given radial position, the maximum value of the radial velocity next to the floor is between 15 and 45% of the tangential velocity in the bulk of the tank. Predicted shear stresses along bounding surfaces were used to obtain correlations for the side-wall and floor friction coefficients in terms of the Reynolds number. These correlations were in turn substituted in an overall moment balance to obtain an analytical model for predicting the maximum tangential velocity Vθw near the side wall of multi-drain rearing tanks. The predictions of the analytical model are in excellent agreement with Vθw values reported in the literature for tanks with diameters ranging from 1.5–15 m and indicate that the drag from inlet structures is non-negligible. The results demonstrate that the axisymmetric CFD model can simulate the main features of the rotating flow inside circular tanks and provide valuable boundary-layer information that is difficult to obtain experimentally.  相似文献   

17.
Optimising Denil fishways for passage of small and large fishes   总被引:1,自引:0,他引:1  
Abstract  An 8-m long experimental fishway was trialled at three different slopes [8.3% (1:12), 14.3% (1:7) and 20% (1:5)] to examine the potential of the single-plane Denil fishway for the passage of small- and large-bodied native fishes in Australia. Fish between 45 and 630 mm ascended the fishway. The lowest slope enabled the full size range of bony herring Nematalosa erebi (Günther), from 45 to 350 mm fork length, to ascend the fishway successfully as well as a higher numerical proportion; 88% at the 8.3% slope compared with 31% at the 20% slope (fish numbers per trial = 33–3936). These results dispel the notion that Denil fishways are inherently poor for small fishes. Manipulating the design parameters of slope, length, width and possibly depth-over-breadth ratio enables Denil fishways to pass a wide size range of fish, which may greatly extend their present application and enable them to make a greater contribution to the rehabilitation of diverse fish communities.  相似文献   

18.
Abstract –  The Goodga River Fishway is the first vertical-slot fishway in Western Australia and was opened in April 2003 with the aim of increasing the habitat available to two galaxiids; the trout minnow ( Galaxias truttaceus ), a highly restricted freshwater fish species in Western Australia, and the widespread common jollytail ( Galaxias maculatus ). The fishway was designed to function during low flows to coincide with the upstream spawning migration of G. truttaceus . Prior to the opening of the fishway, no fish were found above the Goodga River gauging station (weir), which is approximately 2 km upstream of the river's entrance to Moates Lake. Fish migrations were monitored in each season between April 2003 and February 2005. Galaxias truttaceus utilised the fishway in all sampling periods. Adult fish migrated up the fishway prior to spawning, while large numbers of new recruits (small juveniles) negotiated the fishway during November 2003 and 2004. More G. truttaceus and G. maculatus were captured on the fishway during daylight hours compared with the night; however, larger G. truttaceus were more commonly captured at night whereas G. maculatus on the fishway were larger during the day. The fact that fishway utilisation by G. maculatus was consistent during all samples and new recruits migrated during periods of low flow demonstrates the importance of understanding the migration patterns of the target species when designing fishways.  相似文献   

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