共查询到10条相似文献，搜索用时 31 毫秒
1.
In this paper, the motions are studied of a multi-body which is composed of two plates hinged together and moored by eight mooring lines in regular waves. The experimental results are compared with computational results. The linear po-tential theory and the perturbation method are combined to study this complicated system. The former is used to calculate the wave forces acting on the plates and the motion responses of them, while the latter is used to describe the dynamic character of the eight mooring lines coupled with the two hinged plates. Some response results of each plate are presented and comparisons between calculated results and experimental data are given. All the calculations are confined to regular beam waves. 相似文献
2.
An Analytical Solution for Dynamic Response of the Plate with Different Impedances Subjected to Underwater Explosion 
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下载免费PDF全文 In this paper, the transmitted part of the incident wave is considered to revise Taylor’s solution, which is used to extend its application for analytical models to predict the response of the plate with different material properties. The influence of the material properties and the boundary condition of the plate on fluid and structural dynamics is systematically investigated. The analytical results are compared with those of detailed dynamic FE simulations and the two are in good agreement. The results indicate that the analytical method is valid and suitable for the plates with different material properties subjected to underwater explosion. It is found that Taylor’s results of the plate with small impedance are invalid, which indicates a potential application field for the analytical method. 相似文献
3.
Based on the dynamic theories of water waves and Mindlin plates,the analytic solution of interaction between surface waves and two-dimensional floating elastic plates with edge-restraint is constructed by use of the Wiener-Hopf technique.Firstly,without regard for elastic edge restraint,the wave-induced responses of elastic floating plate analyzed by the present method are in good agreement with the results from literature and experimental results.Therefore,it can be shown that the present method is valid.Secondly,three end-restraint cases(i.e.,the left-end elastic restraints,the both-end elastic restraints,and the right-end elastic restraints)are proposed to reduce the vibration of floating plates,in which the spring is used to connect the sea bottom and the floating plate's left(or right)edge.The relations between the spring stiffness and the parameters of wave-induced responses of floating plates are discussed.Moreover,the effective method to reduce the vibration of floating elastic plates can be obtained through comparison. 相似文献
4.
Added mass and damping coefficients are very important in hydrodynamic analysis of naval structures. In this paper, a double submerged inclined plates with ‘/ \’ configuration is firstly considered. By use of the boundary element method (BEM) based on Green function with the wave term, the radiation problem of this special type structure is investigated. The added mass and damping coefficients due to different plate lengths and inclined angles are obtained. The results show that: the added mass and damping coefficients for sway are the largest. Heave is the most sensitive mode to inclined angles. The wave frequencies of the maximal added mass and damping coefficients for sway and roll are the same. 相似文献
5.
On the basis of hydrographic data obtained during two October cruises of 1995, a modified inverse method is used to compute the Kuroshio east of Taiwan and the currents east of the Ryukyu-gunto.The net northward volume transport(VT) of the Kuroshio through Section TK2-K2 southeast of Taiwan is about 57.8×106 m3/s.There are four current cores of the Kuroshio at Section TK2-K2.Its main core is near the south of Taiwan, and its maximum speed is about 257 cm/s at the surface.After the Kuroshio flows through Section TK2-K2, there are three branches of the Kuroshio.The main branch of the Kuroshio flows northward into Section TKa east of Su''ao.The second branch of the Kuroshio flows northward through Section TKa and then enters the East China Sea through the region between Yonakunijima and Iriomote-shima.The net northward VT of the Kuroshio through Section TK4 is about 21.6×106 m3/s.The eastern branch of the Kuroshio flows northeastward through the region between a stronger cyclonic eddy and a recirculating anticyclonic gyre, and then flows continuously northeastward to the region east of the Ryūkyū-guntō and becomes a part of the origin of the western boundary current east of the Ryūkyū-guntō.Another part of the origin of the western boundary current east of the Ryūkyū-guntō comes from a recirculating anticyclonic gyre.From the above, in the regions east of Taiwan end east of the Ryūkyū-guntō the pattern of circulation during October of 1995 differs from the pattern of circulation during early summer of 1985.There are several eddies of different scales in this computational region.For example, there is a meso-scale stronger cyclonic eddy whose center is located at about 23°N, 124°20''E. 相似文献
6.
This is a paper dealing mainly with the accumulation and biological cycle of calcium and magnesium elements of the artificial 20-years old Kandelia candel community in the Jiulongjiang River Estuary of Fujian Province, China.The result of measurements is that the quantities of the two elements in the standing crop are (kg·ha-1) 772.91 for Ca and 526.57 for Mg.In the biological cycle of the two elements, the annual uptakes are 174.86 for Ca and 89.30 for Mg (kg·ha-1); the amounts of Ca and Mg returned via litter fall are estimated to be (kg·ha-1·a-1) 103.28 for Ca and 40.42 for Mg; the annual retention are (kg·ha-1·a-1) 71.58 for Ca and 48.88 for Mg, respectively.The turnover periods of Ca and Mg are 8 and 13 years, respectively. 相似文献
7.
Among numerous offshore structures used in oil extraction, jacket platforms are still the most favorable ones in shallow waters. In such structures, log piles are used to pin the substructure of the platform to the seabed. The pile’s geometrical and geotechnical properties are considered as the main parameters in designing these structures. In this study, ANSYS was used as the FE modeling software to study the geometrical and geotechnical properties of the offshore piles and their effects on supporting jacket platforms. For this purpose, the FE analysis has been done to provide the preliminary data for the fuzzy-logic post-process. The resulting data were implemented to create Fuzzy Inference System (FIS) classifications. The resultant data of the sensitivity analysis suggested that the orientation degree is the main factor in the pile’s geometrical behavior because piles which had the optimal operational degree of about 5° are more sustained. Finally, the results showed that the related fuzzified data supported the FE model and provided an insight for extended offshore pile designs. 相似文献
8.
This paper is concerned with the hydroelastic responses of a mat-like, rectangular very large floating structure (VLFS) edged with a pair of horizontal/inclined perforated anti-motion plates in the context of the direct coupling method. The updated Lagrangian formulae are applied to establish the equilibrium equations of the VLFS and the total potential formula is employed for fluids in the numerical model including the viscous effect of the perforated plates through the Darcy''s law. The hybrid finite element-boundary element (FE-BE) method is implemented to determine the response reduction of VLFS with attached perforated plates under various oblique incident waves. Also, the numerical solutions are validated against a series of experimental tests. The effectiveness of the attached perforated plates in reducing the deflections of the VLFS can be significantly improved by selecting the proper design parameters such as the porous parameter, submergence depth, plate width and inclination angle for the given sea conditions. 相似文献
9.
Masahiro Narukawa Masahiro Sakata Kohji Marumoto Kazuo Asakura 《Journal of Oceanography》2006,62(3):249-257
In Tokyo Bay the concentrations of dissolved gaseous mercury (DGM) in the surface seawater and total gaseous mercury (TGM)
over the sea were measured during December 2003, October 2004 and January 2005. Based on these data, the evasional fluxes
of mercury from the sea surface were estimated using a gas exchange model. In addition, an automatic wet and dry deposition
sampler was used to measure the wet and dry depositional fluxes of mercury from December 2003 to November 2004 at three locations
in and near Tokyo Bay. The results indicate that the average DGM and TGM levels of seven locations are 52 ± 26 ng m−3 and 1.9 ± 0.6 ng m−3, respectively, which shows that the surface seawater in Tokyo Bay is supersaturated with gaseous mercury, leading to an average
mercury evasional flux of 140 ± 120 ng m−2d−1. On the other hand, the annual average wet and dry depositional fluxes of mercury at three locations were 19 ± 3 μg m−2yr−1 and 20 ± 9 μg m−2yr−1, respectively. These depositional fluxes correspond to the daily average total depositional flux of 110 ± 20 ng m−2d−1. Thus, it is suggested that in Tokyo Bay, the evasional fluxes of mercury are comparable to the depositional fluxes. 相似文献
10.
Satellite-based RAR performance simulation for measuring directional ocean wave spectrum based on SAR inversion spectrum 总被引：1，自引：0，他引：1
Some missions have been carried out to measure wave directional spectrum by synthetic aperture radar (SAR) and airborne real aperture radar (RAR) at a low incidence. Both them have their own advantages and limitations. Scientists hope that SAR and satellite-based RAR can complement each other for the research on wave properties in the future. For this study, the authors aim to simulate the satellite-based RAR system to validate performance for measuring the directional wave spectrum. The principal measurements are introduced and the simulation methods based on the one developed by Hauser are adopted and slightly modified. To enhance the authenticity of input spectrum and the wave spectrum measuring consistency for SAR and satellite-based RAR, the wave height spectrum inversed from Envisat ASAR data by cross spectrum technology is used as the input spectrum of the simulation system. In the process of simulation, the sea surface, backscattering signal, modulation spectrum and the estimated wave height spectrum are simulated in each look direction. Directional wave spectrum are measured based on the simulated observations from 0° to 360°. From the estimated wave spectrum, it has an 180° ambiguity like SAR, but it has no special high wave number cut off in all the direction. Finally, the estimated spectrum is compared with the input one in terms of the dominant wave wavelength, direction and SWH and the results are promising. The simulation shows that satellite-based RAR should be capable of measuring the directional wave properties. Moreover, it indicates satellite-based RAR basically can measure waves that SAR can measure. 相似文献