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粒子图像测速技术在河工模型试验中的应用 总被引:4,自引:0,他引:4
近年来计算机图像处理技术有了很大的发展,已在许多生产、科研领域中得到广泛应用,粒子图像测速系统是该技术在河工模型表面流场测量中的应用,它将芯片技术、计算机技术、图像技术和数字信号技术等结合在一起,利用流体中跟随性较好的示踪粒子的成像来测量流体的速度,能实现对模型表面流场的实时采集、处理,最后生成流场矢量分布图,具有测量速度快、精度高、范围广的优点,该系统在南水北调中线穿黄河段河工模型流场测量中取得 相似文献
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文中简要回顾了流动显示技术的发展过程,主要对数字粒子图像测速(DPIV)技术的原理、系统的组成及其在电厂取水流道物理模型试验流道流场测量中的应用作了详细介绍,并给出了流道流场的测试结果,指出DPIV技术将会在无接触流场测试中得到广泛应用。 相似文献
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在河工模型试验中, 粒子图像表面流场测量方法得到了广泛应用。研制了一种新型分布式表面流场测量系统,该系统采用局域网组网与光纤传输相结合,通过POE千兆交换机与高清智能一体化工业摄像机相连,显著降低了布线复杂度,具有系统传输距离远、布设简单、集成度高、可扩展性强等优点。系统具备可视化全自动采集、可视化错误矢量剔除、导出多种数据格式,生成流场等值线图、流线等功能。在系统研制基础上,提出了一种对粒子图像表面流场测量系统进行精度检测的新方法,通过精确控制匀速旋转平台模拟水流运动,将表面流场测量系统实测数据与旋转平台上各点精确数据进行对比检测,检测结果表明,研制的表面流场测量系统测量误差小于5%,已在长江河口模型等多个大型河工模型中得到成功应用。 相似文献
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摆动柔性鳍尾涡流场的实验测试与分析 总被引:3,自引:3,他引:0
利用数字式粒子图像测速系统(DPIV)开展了摆动柔性鳍的尾流场测?分析了尾涡结构的演变过程.柔性尾鳍在一个摆动周期内产生两个反向卡门涡对.本文给出了沿涡对连线及其垂直方向上的速度分布,计算了涡对的速度环量,并初步构建出柔性尾鳍流场中的三维涡环模型. 相似文献
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图像处理技术在河工模型试验流场量测中的应用 总被引:12,自引:1,他引:11
本文系统介绍了图像处理在流场分析中的应用及摄录像系统的配置、操作和计算软件开发的一般原理,对系统的量测误差作了全面的分析并用专门设计的试验进行了检验,量测误差小于1.0%。本文研制开发的流场图像处理系统操作录活,软件功能齐全,能够快速得出全流场表面流速的大小和方向,为河工模型试验提供了一个全新的流场量测方法。 相似文献
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量测技术水平是决定河工模型试验成果质量的关键因素之一。为此,介绍了近期在河工模型断面板制作、河势与流场观测、动床地形三维测量方面的研发成果,包括:提出了基于文本编辑的自动断面板脚本绘制方法,同时结合激光切割机的应用,解决了人工绘制断面板费时费力、数控雕刻机成本高和一般科研人员难以使用等问题;将无人机航拍技术应用于实验室河工模型试验流态、河势和流场观测,与常规固定式摄像机相结合,为试验成果的进一步分析提供了独特视角和丰富、可靠的参考信息;将运动结构恢复三维地形重建技术应用于河工模型冲淤地形测量中,并结合河工模型试验冲淤地形的特点提出具体应用方法。 相似文献
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微机在潮汐模拟和地形自动测量中的应用 总被引:1,自引:0,他引:1
本文介绍了IBM-PC微机和Z80单板机构成分布式流量,水位过程控制和地形自动测量的系统,实现了在河工模型试验中的潮汐模拟和地形自动测量,该系统曾用于“广东省顺德水道三槽口段河工动床模型”和“广东省江门市虎跳门航道整治模型”试验,它具有测控精度高,稳定性好和数据处理能力强等特点。 相似文献
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根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。 相似文献
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The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects. 相似文献
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Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river. 相似文献
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In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment. 相似文献
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V. K. Konovalov O. V. Yashkin V. V. Ermakov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2008,42(2):105-109
A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed
in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash
and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers
of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional
components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect
dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system,
configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants
of dry ash utilization and the advantages of producing of size-separated particles are considered.
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Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008). 相似文献
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Peter B. Bayley 《河流研究与利用》1991,6(2):75-86
The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed. 相似文献