不同排列方式和间隙比下双圆柱流致振动特性研究   总被引：1，自引：0，他引：1  

刘巨保  杨明  岳欠杯  丁宇奇  姚利明 《海洋工程》2018,36(4):105-113

采用基于ALE的流固耦合分析方法,将圆柱体振动模型简化为平面双自由度质量-弹簧-阻尼系统,进行了计算参数无关性分析。对不同θ角和间隙比T下的双圆柱流致振动进行数值模拟,并与单圆柱振动计算结果进行比较,得到了不同θ角和间隙比T下中心圆柱的升阻力系数、流场分布和运动轨迹变化情况。通过分析发现小间隙比下由于两圆柱间的相互干扰,改变了中心圆柱的尾涡结构,导致了升力和阻力系数随不同θ角而发生变化;小间隙比下由于两圆柱间的相互干扰影响,均使中心圆柱的轨迹在不同θ角下发生了较大的变化,顺流向的振动频率与单圆柱振动时相比出现了多倍频,导致其运动轨迹发生了变化。  相似文献   

用层次分析法决策地下水库回灌方案的排序问题     

李云峰  王文科  李志刚  王希宁 《地球科学与环境学报》1992,(2)

本文引用了一种新的系统分析方法(层次分析法)对地下水库人工回灌的复杂系统进行了择优排序研究,取得了满意的结果。实践证明,层次分析法对于地下水库人工回灌方案的择优是一种简捷实用的决策方法。  相似文献   

Drought and institutional adaptation in the Great Plains of Alberta and Saskatchewan, 1914–1939     

Gregory P. Marchildon  Suren Kulshreshtha  Elaine Wheaton  Dave Sauchyn 《Natural Hazards》2008,45(3):391-411

Agriculture in the southern Great Plains of Canada has been particularly vulnerable to prolonged episodes of drought. Using climate data and a precipitation minus potential evapotranspiration index, the extent of the region’s exposure to drought is examined. Between 1914 and 1917, the Dry Belt was particularly vulnerable to drought, whereas after 1928, a much larger region known as the Palliser Triangle covering most of southern Alberta and Saskatchewan was much more exposed to drought. These droughts provoked major institutional adaptation, in particular the establishment of the Special Areas Board by the Government of Alberta, and the creation of the Prairie Farm Rehabilitation Administration by the Government of Canada. Both organizations have proved to be relatively permanent public adaptations to the natural hazard of drought in the region. Moreover, these earlier experiences with prolonged drought as well as institution-building may be of value in helping the residents of the Palliser Triangle adapt to predicted climate changes in the future as well as anticipate some of the barriers to effective institutional adaptation.  相似文献   

National ocean policy—new opportunities for Malaysian ocean development     

Abdul Hamid Saharuddin   《Marine Policy》2001,25(6)

Being a littoral state, Malaysian maritime sectors provide the basis for the growth and development of marine-related activities. As the country enters the new millennium along with the ‘2020 Vision’ which serves as the basic template against which the economic performance of these sectors should be judged, it poses a new challenge for Malaysia in developing these sectors. This paper attempts to address three basic issues: Firstly, is there any national ocean policy in place? Secondly, are the maritime sectors adequately organized to play an important role in achieving the objectives? Thirdly, what are the opportunities available in developing the ocean?It can be seen that existing policies to develop comprehensive ocean governance have not received the full attention they deserve. Organizational structures governing the ocean for implementing national policies are well in place but in a fragmented and uncoordinated fashion. As a result, sectoral and intersectoral management problems were created such as multiple-use conflicts, overlapping of jurisdiction and duplication of efforts. Environmental problems have also not been properly addressed. A few sectors have been identified as offering opportunities to further develop the Malaysian maritime areas. Among these are marine education and human resources development, marine tourism and the seafood industry.  相似文献   

Evaluation of the ocean governance system in Korea     

Dong Oh Cho 《Marine Policy》2006

Considering the small land, dense population and poor natural resources, the oceans are important to Korea, but the recognition of oceans has been weak in Korean society. So ocean governance was fragmented in both institution and policies, which resulted in serious problems in the coastal waters and oceans. However, a series of maritime accidents and failures of policies increased the recognition of the coastal waters and resources and led to the establishment of one single ocean-related governmental agency in 1996. Over the last decade, the ocean governance in Korea has been successful and strong.  相似文献   

倒Y形竖井联系测量   总被引：1，自引：0，他引：1  

曾燕  王利群  唐记城 《现代测绘》2008,31(3)

介绍在小直径竖井联系测量中取消联系三角形,改用单根钢丝定点,全站仪引测高程的施测方法。  相似文献   

Planning for source water protection in Ontario   总被引：2，自引：0，他引：2  

J.L. Ivey  R.C. de Loë  R.D. Kreutzwiser 《Applied geography (Sevenoaks, England)》2006,26(3-4):192-209

Ontario began developing a drinking water source protection planning process in 2000, after a rural community's water supply was contaminated by pathogens from agricultural runoff. An expert committee report has recommended legislating a new source protection “sphere of jurisdiction” for municipalities; however, no specific new municipal tools or authorities have been proposed as yet. This paper reports findings from an evaluation of the extent to which existing institutional arrangements for land use planning and water management facilitate or constrain source protection by municipalities. A case study of the Regional Municipality of Waterloo suggests there is the potential to link land use planning more strongly to water management through creative use of existing tools, forgoing the need for major institutional changes.  相似文献   

地下管线探测工程的资料自动化整理   总被引：1，自引：0，他引：1  

阎金梅 《化工矿产地质》2003,25(4):240-242,250

地下管线探测工程一般分为野外探测和室内资料整理两阶段。内业整理包括成果表的编制、管线综合分布平面图和管线数据库。由于管线探测工程数据多,为了充分利用外业探测成果,应用Visual Basic 6.0(VB6)开发了一套地下管线管理信息系统(UTMIS),该系统实现了地下管线探测工程内业整理的自动化,极大地提高了工作效率数据精确度。  相似文献   

应用Kriging方法研究格尔木河流域地下水位动态观测网的优化配置   总被引：4，自引：0，他引：4  

宋儒 《中国煤田地质》1997,(4)

地下水动态是水文地质研究的一个重要方面，如何获满足一定精度要求全面而合理的地下水位动态资料具有现实经济效益。本文研究格尔木河流域地下水位动态测网，通过选取理想的变差函，运有Ｋｒｉｇｉｎｇ方法进行地下水位的线性无偏最优估计和计算估计误差的标准差，结合给定的允许误差限评判地下水位动态观测网的配置是否合适，并提出调整现有观测网的方案  相似文献   

A model for integrated spatial land use characteristics linking to surface nutrient concentration   总被引：1，自引：0，他引：1  

Erqi Xu 《International Journal of Digital Earth》2018,11(10):1064-1084

Quantifying land use heterogeneity helps better understand how it influences biophysical systems. Land use area proportions have been used conventionally to predict water quality variables. Lacking an insight into the combined effect of various spatial characteristics could lead to the statistical bias and confused understanding in previous studies. In this study, using spatial techniques and mathematical models, a diagnostic model was developed and applied for quantifying and incorporating three spatial components, namely, slope, distance to sampling spots, and arrangement. The upper catchment of Miyun Reservoir was studied as the test area. Total nitrogen, total phosphorus, and chemical oxygen demand of water samples from field measurements were used to characterize the surface water quality in 52 sub-watersheds. Using parameter calibrations and determinations, combined spatial characteristics were explored and detected. Adjusted land use proportions were calculated by spatial weights of discriminating the relative contribution of each location to water quality and used to build the integrated models. Compared with traditional methods only using area proportions, our model increased the explanatory power of land use and quantified the effects of spatial information on water quality. This can guide the optimization of land use configuration to control water eutrophication.  相似文献