The reflection of oblique waves by an infinite number of partially perforated caissons     

Yong Liu  Yu-cheng Li  Bin Teng 《Ocean Engineering》2007,34(14-15):1965-1976

This study examines the reflection of obliquely incident waves by an infinite array of partially perforated caissons. Based on the linear potential theory, an analytical solution of the present problem was developed by means of the matched eigenfunction expansion method. The solution was obtained in a single strip consisting of the semi-infinite narrow region in front of a caisson and the fluid domain inside this caisson. It was then extended to the whole fluid domain by using the periodicities of the structure and the incident waves along the length of the caissons. The present model was validated by comparing the reflection coefficients of several limiting cases with the corresponding results obtained by previous researchers. Numerical experiments were also conducted to examine the variations of the reflection coefficient versus its main effect factors. The numerical results indicate the differences between the present model and the previous limiting cases, and some helpful results are recommended for practical engineering.  相似文献   

Hydrodynamic behavior of a straight floating pipe under wave conditions   总被引：2，自引：0，他引：2  

Yucheng Li  Fukun Gui  Bin Teng 《Ocean Engineering》2007,34(3-4):552-559

This paper examines the hydrodynamic behavior of a floating straight pipe under wave conditions. The main problem in calculating the forces acting on a small-sized floating structure is obtaining the correct force coefficients C_n and C_t, which differ from a submerged structure. For a floating straight pipe of small size, we simplify it into a 2D problem, where the pipe is set symmetrically under wave conditions. The force equations were deduced under wave conditions and a specific method proposed to resolve the wave forces acting on a straight floating pipe. Results of the numerical method were compared to those from model tests and the effects of C_n and C_t on numerical results studied. Suggestions for the selection of correct C_n and C_t values in calculating wave forces on a straight floating pipe are given. The results are valuable for research into the hydrodynamic behavior of the gravity cage system.  相似文献   

Modified eigenfunction expansion methods for interaction of water waves with a semi-infinite elastic plate     

B. Teng  L. Cheng  S. X. Liu  F. J. Li 《Applied Ocean Research》2001,23(6)

The eigenfunction expansion method (will be referred to as error function method in this paper) of analysing reflection and transmission of ocean waves at a semi-infinite thin elastic plate [J Geophys Res 95 (1990) 11629; Phil Trans R Soc Lond A 347 (1994) 185] is modified and extended to cases with simply supported and built-in edges. The form of the error function in the eigenfunction expansion method of Fox and Squire [J Geophys Res 95 (1990) 11629] has been modified based on a dimensional analysis and also extended to plates with either a simply supported or a built-in edge. The modified error function does not include the so-called Lagrange multipliers used in the original method and therefore the modified solution is independent of the selection of the Lagrange multipliers. It is demonstrated that the modified error function method satisfies the relation of energy conservation very well for the three edge conditions examined. The relation of energy conservation for plates is derived for elastic plates with simply supported and built-in edges and it is found that the relation of energy conservation for a free edge is also held for simply supported and built-in edges.In addition, a minor modification has also been made to the eigenfunction method (will be called inner product method in this study) of Sahoo et al. [Proceedings of 10th International Offshore and Polar Engineering Conference 3 (2000) 594]. It will be shown that the modified inner product method becomes mathematically well defined. The modified coefficient matrixes for different edge conditions are diagonal and thus the linear simultaneous equations can be solved very easily. It is also demonstrated with examples that the extended error function method and the modified inner product method give identical results.  相似文献   

Application of the four models of directional spectra in the Bohai Sea     

Wu Xiujie  Teng Xuechun 《海洋学报(英文版)》1995,14(1):15-22

ＡｐｐｌｉｃａｔｉｏｎｏｆｔｈｅｆｏｕｒｍｏｄｅｌｓｏｆｄｉｒｅｃｔｉｏｎａｌｓｐｅｃｔｒａｉｎｔｈｅＢｏｈａｉＳｅａ￥ＷｕＸｉｕｊｉｅａｎｄＴｅｎｇＸｕｅｃｈｕｎ（ＦｉｒｓｔＩｎｓｔｉｔｕｔｅｏｆＯｃｅａｎｏｇｒａｐｈｙ，ＳｔａｔｅＯｃｅａｎｉｃＡ...  相似文献   

海浪方向谱的阵列测量     

吴秀杰  初乃良  郭洪梅  滕学春  束美新 《海洋科学进展》1992,(4)

本文在系统分析国内外有关方向谱测量工作的基础上,根据实验室模型试验结果,采用由五个测波仪组成的“T”形阵列,于1991年6～7月同在渤海8号采油平台上首次进行了方向谱阵列测量,获得了宝贵的阵列测量资料。测量实施表明,选择最佳测量方案及性能稳定的测波仪器,对测量结果是至关重要的。  相似文献   

Influence of Certain Organic Substances on Growth and Colony Formation of Asterionella glacialis Castracane (Bacillariophyceae)     

Tzu-Chiu  Teng 《Marine Ecology》1984,5(4):317-327

Abstract. Organic substances are suspected to influence the unpredictable, episodic blooms which characterize the planktonic pennate diatom Asterionella glacialis in certain coastal waters. Experiments to test its general responsiveness to organic enrichments in terms of growth rate and colony formation were carried out. An axenic clone was grown at 10° C, 0.039 l min^-1,12:12 LD cycle in G uillard's f/2 medium enriched with eight different organic substances. Growth rates in organically-enriched media during exponential phase usually exceeded those in f/2 medium alone. Cell yields after 12 days in media enriched with glycyl-glycin and trypticase + yeast extract were significantly greater than in the other treatments. Longer chain lengths accompanied organic enrichment, notably with trypticase + yeast extract and 100ppm soil extract. These results suggest that Asterionella glacialis is positively responsive to elevated levels of certain organic substances. A potential effect of organic substance - trace metal - silica interactions on colony-size is suggested.  相似文献   

Wave Breaker Indices in Finite Water Depth   总被引：2，自引：0，他引：2  

Li Yucheng  Dong Guohai Teng Bin Professor  Civil Engineering Department  Dalian University of Technology  Dalian Ph. D. Student  Dalian University of Technology  Dalian Research Assistant  Doctor of Engineering  Dalian University of Technology  Dalian 《中国海洋工程》1991,(1)

Based on the analysis and comparison of wave breaker indices defined by geometric, kinetic as well as dynamic stabilities and verified by observation, the value a, which is equal to H / Lthkd by Miche's result and may be modified by Goda's results, is" suggested as the wave breaking criteria. The applicable values of a for pure waves or wave-current co-existing field are given in this paper. They are smaller than Miche's result (0.142), and they have been verified by model tests.  相似文献   

A new model (DRARCH) for assessing groundwater vulnerability to arsenic contamination at basin scale: a case study in Taiyuan basin,northern China   总被引：7，自引：0，他引：7  

Qinghai Guo  Yanxin Wang  Xubo Gao  Teng Ma 《Environmental Geology》2007,52(5):923-932

A modified DRASTIC model for groundwater vulnerability assessment (abbreviated as DRARCH model by combining the first letters of its six assessment indices) was proposed. It is essentially the specific application of DRASTIC model rather than a new model. Both natural hydrogeological conditions that prevent groundwater from contamination and important intrinsic hydrogeochemical properties of sediments in vadose zone that are related to the retardation of contaminants were considered as vulnerability indices. The DRARCH model consists of six indices: (1) Depth to the water table, (2) net Recharge, (3) Aquifer thickness, (4) Ratio of cumulative thickness of clay layers to total thickness of vadose zone, (5) Contaminant adsorption coefficient of sediment in vadose zone, and (6) Hydraulic conductivity of aquifer. The rating values and the weights of these vulnerability indices were obtained by contaminant transport simulation and factor analysis method respectively. Furthermore, the DRARCH model was applied to evaluate the groundwater vulnerability to arsenic contamination in Taiyuan basin, northern China, where groundwaters with high arsenic concentration occur in some localities. GIS-based mapping of groundwater vulnerability using this model indicates that the distribution of very high and high-vulnerability areas corresponds well to that of high-arsenic groundwaters. The DRARCH model is therefore reliable and useful for guiding groundwater environment management.  相似文献   

Common reflection surface stack using dip decomposition for rugged surface topography   总被引：1，自引：0，他引：1  

孙小东李振春  滕厚华 《应用地球物理》2007,4(1):45-50

We present an extension of the Common Reflection Surface （CRS） stack that provides support for an arbitrary top surface topography. CRS stacking can be applied to the original prestack data without the need for any elevation statics. The CRS-stacked zero- offset section can be corrected （redatumed） to a given planar level by kinematic wave field attributes. The seismic processing results indicate that the CRS stacked section for rugged surface topography is better than the conventional stacked section for S/N ratio and better continuity of reflection events. Considering the multiple paths of zero-offset rays, the method deals with reflection information coming from different dips and performs the stack using the method of dip decomposition, which improves the kinematic and dynamic character of CRS stacked sections.  相似文献   

浙江省降水云系红外云图特征及其与降水量的关系   总被引：2，自引：0，他引：2  

滕卫平  杜惠良胡波 俞善贤 《气象科技》2006,34(5):527-531

用2000~2003年GMS红外云图资料,统计分析了影响浙江省降水系统的红外云图特征及其与地面1 h降水量的关系。结果表明:降水云团的云顶亮温、1 h云顶亮温差、云顶亮温梯度和云团移动速度与地面降水强度的对应关系是非线性的,并且随季节的变化它们的关系又有明显变化;随着云顶亮温的降低,1 h降水量降水强度逐渐增大,出现强降水的机率也明显增多;浙江省内易出现2.0 mm/h(中雨)7、.0 mm/h(大雨)、15.0 mm/h(暴雨)强降水的云顶亮温指标分别为-30℃、-36℃、-41℃。  相似文献