A Fully Nonlinear HOBEM with the Domain Decomposition Method for Simulation of Wave Propagation and Diffraction     

Sheng-chao Jiang  Ze-hang Shi  Chao Song  Gui-yong Zhang  Guo-qiang Tang 《中国海洋工程》2018,32(6):646-654

A higher-order boundary element method (HOBEM) for simulating the fully nonlinear regular wave propagation and diffraction around a fixed vertical circular cylinder is investigated. The domain decomposition method with continuity conditions enforced on the interfaces between the adjacent sub-domains is implemented for reducing the computational cost. By adjusting the algorithm of iterative procedure on the interfaces, four types of coupling strategies are established, that is, Dirchlet/Dirchlet-Neumman/Neumman (D/D-N/N), Dirchlet-Neumman (D-N), Neumman-Dirchlet (N-D) and Mixed Dirchlet-Neumman/Neumman-Dirchlet (Mixed D-N/N-D). Numerical simulations indicate that the domain decomposition methods can provide accurate results compared with that of the single domain method. According to the comparisons of computational efficiency, the D/D-N/N coupling strategy is recommended for the wave propagation problem. As for the wave-body interaction problem, the Mixed D-N/N-D coupling strategy can obtain the highest computational efficiency.  相似文献   

简单随机模式进一步分析(Ⅰ)——非线性外通函数项处理     

唐佑民 《成都信息工程学院学报》1992,(1)

本文利用等效线性化法和Fokker-planck方程,对一个简单的非线性随机模式非线性项在不同气候时期的参数化进行了讨论,得到了冰期、间冰期和现代气候的概率分布密度及输出响应特征。  相似文献   

International Symposium on Five Decades of Radioglaciology,International Glaciological Society          下载免费PDF全文

Tang Xueyuan 《极地研究》1988,31(4):490

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景泰地震前后兰州台的中期形变异常     

唐九安  常千军  彭伟荣  周志宇 《大地测量与地球动力学》1995,(3)

给出了兰州台浮子水管倾斜仪和石英伸缩仪１９８７～１９９３年间Ｍ２波潮汐因子的年度调和分析结果，然后对各分量月均值进行了残差分析，并绘出去除长期项后的倾斜矢量图，据此探讨了景泰地震的中期前兆异常和震后效应特征。  相似文献   

一种新的射电源表综合方法   总被引：1，自引：0，他引：1  

唐正宏  须同祺 《天文学报》1996,37(3):320-326

本文提出利用正交完备函数系拟合射电源表的局部系统差，并通过选择初始星表确定综合射电源表系统的轴方向，在综合计算时以射电源表包含的所有源坐标决定其轴方向．整个综合过程概念清晰，计算量较小．检验结果表明，用新方法得到的综合射电源表可靠性与稳定性都很好．  相似文献   

Flare morphologies and coronal field configurations     

Frances Tang 《Solar physics》1985,102(1-2):131-145

Chromospheric flares are the footpoints of closed coronal field lines. In this paper we present different flare morphologies from observations and examine the implied coronal field configurations above the flaring region. Flares are grouped according to the number of ribbons, from unresolved compact point-like flare to four-ribbon flares. Quiet region flares having characteristics all their own are also presented here.We find that compact, unresolved point-like flares have two distinct footpoints when viewed in offband H. The footpoints of some of the compact flares also show increased separation as a function of time.Unlike large two-ribbon flares, the ribbons of many small and/or short-lived two-ribbon flares usually have no measurable separation of ribbons.Multiple-ribbon (three or more ribbon) flares consist of two or more pairs of two-ribbons, or two or more sets of field lines. Parity of the ribbons in multiple-ribbon flares, or the lack of it, depends on the magnetic makeup of the locale of the ribbons.Flares in old quiet regions resulting from sudden filament eruptions show discrete small patches of emissions reflecting the spottiness of decayed and dispersed field of quiet region.  相似文献   

广西秋季层状云微物理特征分析   总被引：1，自引：0，他引：1  

张正国  卢广献  汤达章  韦增岸 《气象科技》2018,46(3):545-555

利用2012年11—12月在广西进行的11架次飞机云物理探测资料对层状云宏微观物理结构特征进行研究,探讨层状云降水机制。结果表明:广西层状云微物理特征与我国其他地区的存在显著差异。层状云典型的微物理垂直结构为在云下层是由凝结作用生成云滴,随上升气流发展,云滴数浓度、平均直径和液态水含量随高度逐步增加,云滴谱拓宽,谱型向大尺度的方向扩展,至云中上层增大至最大值后随高度减小。冷暖混合云结构的高层云冷云部分的冰相粒子落入暖层后对其微物理结构产生影响,主要是使云滴谱展宽,CIP云滴平均直径垂直分布变幅增大,有利于暖层中碰并过程的启动和发展。层积云微物理水平分布呈现不连续跳跃式变化特征,存在对流泡结构,对流泡内各微物理量高于泡外,云滴谱型向大尺度移动,对流泡结构是层积云形成降水的重要机制。  相似文献   

Potential impacts of climate change on storage conditions for commercial agriculture: an example for potato production in Michigan     

Julie A. Winkler  Logan Soldo  Ying Tang  Todd Forbush  David S. Douches  Chris M. Long  Courtney P. Leisner  C. Robin Buell 《Climatic change》2018,151(2):275-287

Climate change is anticipated to influence all parts of agricultural production systems. However, the potential impacts on crop storage have rarely been assessed, even though storage is an important component of a grower’s marketing strategy and is essential for the continuous supply of a commodity for processors, exporters, and consumers. The Michigan chip-processing potato industry provides an example of the importance of crop storage. Michigan is the largest producer of chip-processing potatoes in the USA, and potatoes are stored on farms from September to June. We use an ensemble of climate projections developed for three future time slices (early, mid, and late century) from 16 climate models forced by three greenhouse gas concentration pathways to assess future changes in potato storage conditions. Our findings indicate an increased future demand for ventilation and/or refrigeration immediately after harvest and again in spring and early summer, even for the early-century time slice. Furthermore, the period of reliably cold storage temperatures during winter is anticipated, when averaged across all models, to shorten by 11–17 days in Michigan’s primary production area and 14–20 days in the more southern secondary area by mid-century, and by 15–29 days and 31–35 days, respectively, for the northern and southern production areas by late century. The level of uncertainty, as indicated by the ensemble range, is large, although the sign of the projected changes in storage parameters is consistent. This case study provides an example of the potentially large effects of climate change on the storage conditions for agricultural commodities.  相似文献   

Proof of homothally of Pheopolykrikos hartmannii and details of cyst germination process     

Chai  Zhaoyang  Hu  Zhangxi  Liu  Yuyang  Tang  Yingzhong 《中国海洋湖沼学报》2020,38(1):114-123

Resting cysts play crucial roles in the ecology of dino?agellates, especially in wintering or surviving unfavorable conditions, seeding harmful algal blooms(HABs), and facilitating the geographic expansion. Encystment of dino?agellates is tightly coupled with sexual reproduction in most cases, which can occur either through homothallism(self-fertilization) or heterothallism(intercrossing of +/-strains). The types of sexual reproduction have important ecological implications. The toxic and HAB-forming dino?agellate, Pheopolykrikoides hartmannii has been previously reported to be heterothallic. Here, we provide visual con?rmation of homothally of P. hartmannii and the ?rst detailed visual recording of cyst germination based on the observations of a clonal isolate from Jiaozhou Bay, China. To document the homothallism, we ?rst observed cell pairs in sexual mating, planozygotes with two longitudinal ?agella, and cysts with typical morphology as described previously from the clonal culture. We then germinated a single cyst, established a new clonal culture from one of the two daughter cells after the ?rst cell division of the germling(i.e. from the diploid germling to two haploid cells), and produced cysts again from the newly established clonal culture. For the observation of the germination time-series, we took micrographs and videos to show all germination processes, particularly with an interesting observation of the short amoeboid stage of the germling releasing from the archeopyle(～15 s), which was a landmark of the germination process and has not been reported elsewhere. This de?nitive evidence of homothallic sexuality and cyst production in P. hartmannii provides a new insight into the biology and ecology of the species, particularly a mechanism that may partly account for the population dynamics and ubiquitous distribution of the species.  相似文献   

Sedimentary charateristics and hydrocarbon accumulation in Northeast Sichuan basin     

Jianming Li  Xiling Wu  Rufeng Li  Liangjie Tang  Lei Li 《Frontiers of Earth Science》2008,2(1):120-125

Northeast Sichuan basin is a Mesozoic-Cenozoic basin in the northern margin of the Yangtze plate which has a complex tectonic background and hydrocarbon accumulation history. By means of the analysis method of wave processes, major cycles of sedimentary wave process in this basin have been studied. The results show that there are five-order cycles corresponding to 760, 220, 100, 35 and 20 Ma respectively, two first-order sedimentary cycles (220 Ma) and four secondorder sedimentary cycles (100 Ma). The authors find that the second-order sedimentary cycles are well matched with reservoir formation cycles through studying the relationship between second-order sedimentary cycles and reservoir formation cycles, and divide three reservoir formation cycles in this basin. __________ Translated from Journal of Jilin University (Earth Science Edition), 2007, 37(3): 513–518 [译自: 吉林大学学报(地球科学版)]  相似文献