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王建强  赵国强  朱广彬 《大地测量与地球动力学》2009,29(2):126-130

?????????????????????????????????????????ε??????o??????????????????4????????????o?????????????:??????????????????????????Belikov ?????????ε??????????????????????????????????????????????????????θ???3 060??????????????????????????,???ε????????????ε??????o?????????????  相似文献   

Hydrodynamic loads during the deployment of ROVs   总被引：1，自引：0，他引：1  

P. Sayer   《Ocean Engineering》2008,35(1):41-46

Offshore operators understandably seek to operate remotely operated vehicles (ROVs) for as long as possible and in the widest range of sea conditions. Accurate predictions of the hydrodynamic loads are important at the design stage as well as in operation, particularly during the launch and recovery phases when snatching of the tether may occur. There is some speculation that calculation methods currently advocated in guidelines lead to an over-estimation of the hydrodynamic forces and consequently to unduly restrictive operability constraints. The present paper has measured wave forces on a 1/8 scale model of a widely used ‘workclass’ ROV, as well as on a solid box of similar envelope dimensions, and compared these against Morison's equation using coefficients derived from three methods. It is concluded that simple linear theory using total (substantive) derivatives, together with a Morison coefficient C_m≈1.5, can provide good estimates of the loading even in waves of quite high steepness, perhaps for height-to-wavelength ratios up to 0.08; i.e., in practice, up to wave breaking.  相似文献   

A parametric study of wave loads on trimaran ships traveling in waves   总被引：3，自引：0，他引：3  

Ming-Chung Fang  Tse-Yin Chen 《Ocean Engineering》2008,35(8-9):749-762

In this paper, we present a spectral analysis based on wave loads to select suitable side-hull arrangements for a trimaran ship traveling in waves. Neglecting the steady flow effect, the three-dimensional source-distribution method, using a pulsating source potential incorporating the panel method, is adopted to solve the corresponding hydrodynamic coefficients. The significant values for wave loads, including shear forces, bending moments, and torsion moments at different locations on the main hull and connected deck with respect to different staggers and clearances, are derived by the spectral analysis. Several ship speeds and wave headings are also considered for comparison. This study offers more information for selecting the side-hull arrangement from the viewpoint of wave loads on trimaran ships, which may be regarded as helpful references for seakeeping design of these types of ships.  相似文献   

The observed currents in summer in the Bohai Sea   总被引：3，自引：0，他引：3  

乔璐  鲍献文  吴德星 《中国海洋湖沼学报》2008,26(2):130-136

A harmonic method was used to analyze the tidal currents observed in summer at 11 stations made from 1996 to 2001 in the Bohai Sea, China. Data was compared among different instruments and intervals. Elliptic elements were calculated based on harmonic constants, of which vertical distributions of the maximum speed and rotation direction were discussed for understanding the characteristics of diurnal and semi-diurnal tidal current components. The results indicate that the maximum speed of M2 tidal current component is much larger than that of K1; the rotation direction of M2 tidal current constituent is clockwise in the central part of the Bohai Sea and in the Laizhou Bay, but anticlockwise in the Liaodong Bay and Bohai Bay. For K1 tidal current constituent, it is clockwise in the central Bohai Sea but anti-clockwise in the Laizhou Bay and Liaodong Bay. The tidal currents in most stations in the Bohai Sea were regular semidiurnal except for those in the central Bohai Sea, being irregular semidiurnal.  相似文献   

Multi-photon resonance enhanced super high-order harmonic generation     

林正喆  庄军  宁西京 《海洋学报(英文版)》2010,29(11)

This paper proposes highly charged ions pumped by intense laser to produce very high order harmonics. Numerical simulations and full quantum theory of Ne⁹⁺ ions driven by laser pulses at 1064 nm in the power range of 10⁹ W/cm² ～ 10¹⁵ W/cm² show that the emission spectrum corresponds to the electronic transitions from the excited states to the ground state, which is very different from the spectrum of general high-order harmonic generation. In such situation, harmonic order as high as 1000 can be obtained without producing lower order harmonics and the energy conversion efficiency is close to general high order harmonic generation of hydrogen atom in the same laser field.  相似文献   

重庆武隆M5.0地震前地磁异常特征分析          下载免费PDF全文

翁骋  戴苗  王弘宇  王秋良 《地震工程学报》2021,43(3):559-564

选取恩施台、涪陵江东台、石柱黄水台以及武隆仙女山台2012年1月至2017年11月地磁数据进行异常分析,得到各个台站的地磁谐波振幅比和加卸载响应比计算结果,并结合2017年11月23日重庆武隆M5.0地震震中附近地质构造背景分析地震前后地磁异常现象。分析结果认为大部分地磁谐波振幅比变化特征类似于地电阻率的变化特征,表现为"下降-转折-上升"过程。本次地震大致发生在转折上升的初期阶段,其中震中距较小的台站地磁谐波振幅比变化趋势不同步,但变化幅度大致相同,而震中距较大的台站地磁谐波振幅比变化趋势较为同步,变化幅度较大。此外,研究还表明震前地磁加卸载响应比异常高值在时空分布上与震中位置具有很好的对应关系。  相似文献   

Photogravitational magnetic-binary problem with oblateness and belt of material points     

《New Astronomy》2022

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胶州湾海面溢油轨迹的数值模拟   总被引：1，自引：0，他引：1  

娄安刚  王学昌  孙长青  奚盘根 《海洋科学进展》2001,19(1):1-8

对胶州湾湾口两侧——团岛和薛家岛 1个月的潮位观测资料进行调和分析 ,得出湾口两侧 M2 ,S2 ,O1,K1分潮的调和常数 ,进而建立了胶州湾内的预报潮流场。考虑风场对海面溢油的影响 ,给出了预测胶州湾溢油飘移轨迹的数值模型 ,对 1 983年 1 1月 2 5日“东方大使”号油轮在中砂礁触礁后的溢油的油膜漂移轨迹进行了数值模拟 ,结果与事故后观测到的结果相符 ,说明了数值模拟的正确性  相似文献