大开口型船舶在不规则波中的波浪导矩预报分析

综述了现有船舶波浪扭矩的计算分析方法，用ＳＴＦ切片理论方法计算了大开口船舶波浪扭矩的传递函数。根据不同波谱理论模型对规则波中的扭矩作了统计预报，讨论了小姐浪扭矩予报对波谱的敏感性。研究结果表明，波浪扭矩对波谱谱型的依赖程度相当大；特征波浪周期对统计值的影响比有义波高在；对相同有义波高，ＰＭ谱相应的预报值比ＩＴＴＣ二参数谱的结果更偏于保守。     

扁平船舶波浪载荷预报研究

针对宽深比比较大的扁平船,研究了船舶波浪载荷长短期预报的直接计算方法。基于三维频域线性水动力理论,通过分析得出波浪载荷的响应幅算子,采用谱分析法对波浪载荷进行长短期期预报。以某试验船为例进行了计算并将结果与规范值进行了比较。得到的结论对扁平船船体强度的评估研究提供了重要参考,也为其他相关方面的研究提供了一定的借鉴价值。     

“育明”轮波浪载荷直接计算研究

基于三维无航速格林函数理论,采用了Hydro STAR软件,对上海海事大学教学实习船"育明"轮进行波浪载荷预报,包括其在4种工况中的波浪载荷短期以及长期预报。短期预报采用Jonswap谱,长期预报采用IACS推荐的北大西洋波浪散布图,并与IACS最新推出的共同规范HCSR的规范值进行了比较。计算结果表明,在恶劣海况下,船舶遭受的波浪载荷不容小觑,不仅需要用规范进行计算,更需要对其进行直接计算以确保船舶营运的安全性。     

波浪弯矩设计值与长期预报理论计算值的比较

本文分析了国际船级社协会（ＩＡＣＳ）纵向强度标准Ｓ１中，波浪弯矩值成采用ＩＡＣＳＷＰ／Ｓ委员会推荐的海浪谱和海况统计资料条件下的长期预报理论计算值的关系，大量计算实践表明后者总体上要比前者大１．５倍。文中建议为了把长期技术应用于船体波浪弯的直接设计计算，对上述预报过程可取１０概率水平时地长期预报值作为船体波浪湾矩设计值。     

基于海况参数分析的船体梁载荷预报方法研究

利用三维势流理论在频域内计算载荷频率响应函数,在此基础上对船舶波浪载荷长短期预报方法进行了研究,分析了现有的长期预报方法,并提出只针对特定的一部分短期海况进行分析,以确定船舶在营运寿命期内航行于实际海况中的波浪载荷特征最大值。同时提出了一种基于多项式拟合的波浪载荷预报方法,建立了短期响应的最可能极值关于海浪有义波高与海浪平均向上跨零周期的函数,可以方便地确定响应的特征值。结果表明,提出的方法能够有效进行波浪载荷的预报,可供有关专业人员参考。     

基于切片理论的波浪载荷直接计算

提出了波浪载荷直接计算方法。该方法基于线性切片理论,在频域范围内进行。通过水动力分析得出波浪载荷的响应幅值算子,采用统计方法对波浪载荷进行长期预报,并将线性波浪载荷预报结果进行非线性修正,以模拟实际波浪载荷的非线性效应。最后以某一船型为例,结合IACS推荐的波浪谱和波浪散布图以及超越概率,采用该方法进行了计算并将计算结果与规范值进行了比较。     

IACS波浪弯矩设计值与长期预报理论计算值的比较

本文分析了国际船级协会（ＩＡＣＳ）纵向强度标准Ｓ１１中波浪弯矩设计值与在采用ＩＡＣＳ ＷＰ／Ｓ委员会推荐的海浪谱和海况统计资料条件下的长期预报理论计算值的关系，大量计算实践表明后者总体上要比前者大１．５倍，文中最后建议为了把长期预报这一技术应用于船体波浪弯矩的直接设计计算，对上述预报过程可取１０＾－５．５概率水平时的长期预报值作为船体波浪弯矩设计值。     

不同海浪谱对船舶载货系统运动响应分析的影响

本文从船舶远洋运输角度对三种典型海浪谱的特性进行了研究,利用三维势流理论对船舶频域统计进行分析,在同一气象环境参数下,分别计算了Neumann谱、P-M谱和JONSWAP谱对船舶载货系统的运动响应短期预报极值,得到了P-M谱和JONSWAP谱下设备模块运动加速度等短期预报值的相近,而Neumann谱下设备模块运动加速度等短期预报值偏小的结果。说明根据技术条件慎重选择海浪谱进行船舶载货系统运动响应分析十分关键。     

内河船舶波浪载荷研究

利用内河波浪散布图和修订波浪谱对内河系列船舶进行了波浪载荷的计算预报,首次分析了内河船舶波浪载荷的规律和特点,并与俄罗斯内河登记局(RRR)和法国-德国船级社(B-G)的内河规范载荷对应的等效模数要求进行了比较分析。结合实船测试结果表明：波浪载荷变化规律与国外同类规范一致,预报波浪载荷水平与测试结果及国外同类规范要求相当。内河船舶波浪载荷预报应考虑航速和水深的影响,载荷预报结果可以作为制定内河波浪载荷公式的基础。     

最大熵原理在船舶波浪载荷理性预报中的应用

本文介绍最大熵原理及其在船舶波浪载荷理性预报中的应用,详细地叙述了船舶随机波浪弯矩概率密度函数的求取原理与方法,通过二个实际船舶的例子,给出了这二艘船舶随机波浪弯矩概率密度函数及其统计推断值,显现出波浪载荷的理性预报方法及其最大熵方法的良好应用前景.     

Design safety margin of a 10,000 TEU container ship through ultimate hull girder load combination analysis

Assessment of the ultimate longitudinal strength of hull girders under combined waveloads can be of particular importance especially for ships with large deck openings and low torsional rigidity. In such cases the horizontal and torsional moments may approach or exceed the vertical bending moment when a vessel progresses in oblique seas. This paper presents a direct calculation methodology for the evaluation of the ultimate strength of a 10,000 TEU container ship by considering the combined effects of structural non-linearities and steady state wave induced dynamic loads on a mid ship section cargo hold. The strength is evaluated deterministically using non-linear nite element analysis. The design extreme values of principal global wave-induced load components and their combinations in irregular seaways are predicted using a cross-spectral method together with short-term and long-term statistical formulations. Consequently, the margin of safety between the ultimate capacity and the maximum expected moment is established.     

登陆台风对长江口口门水域的影响

针对登陆台风对长江口口门水域产生的影响问题,采用统计学方法对3次登陆台风期间现场采集的长序列定点观测资料进行系统分析。结果表明,台风登陆后有效波周期减小至常态天气水平,未出现长周期涌浪;台风登陆前水位抬升,最大增水与最大有效波高均出现在登陆前高潮时;台风登陆前有效波高在2 m以上时,波浪对口门处由南向北的横向流速分量起到抑制作用;其他时段,口门处由南向北的横向流速分量变化与涨潮过程一致。     

Derivation of wave spectrum using data driven methods

The current techniques of derivation of a wave spectrum from given values of design wave parameters, like significant wave height and average wave period, are fraught with considerable uncertainties. This leaves scope for alternative approaches. The reported work proposes potential applications of two recent data driven methods, namely support vector regression (SVR) and model tree (MT), to obtain the wave spectra. In the present study the above tools were used to estimate wave spectra at two locations: no. 44008 maintained by National Data Buoy Centre (NDBC) in the Gulf of Maine, USA and ‘DS5’ monitored by National Institute of Ocean Technology (NIOT) in Bay of Bengal, India. The choice of these two locations facilitated the comparison of model performances in different geographical areas. The SVR and MT models were developed in order to estimate the wave surface spectral density over a wide range of wave frequencies out of average wave parameters of significant wave height and average zero-cross wave period. The models were trained and tested using randomly selected sea states. Both MT and SVR were able to derive the spectral shapes satisfactorily as reflected in high values of the correlation coefficients and low values of root mean square error and mean square error.     

台风波高重现值的泊松最大熵分布估计

以日本中城湾观测站实测台风过程出现的最大波高序列为例,提出了泊松-最大熵复合极值分布,并将其用于计算台风海浪的重现值波高.采用年极值法与过阈法对台风波高进行长期统计分析.计算结果表明:观测时段相同,阈值的选取对重现值的估计影响不大.而阈值相同,抽样时段的长度对重现值估计的影响较大;若样本时段较短,但极值波高的最大值包含于其中,则估计得到的重现值偏大,该结果对于结构设计是偏安全的.     

里海南部海岸在极浅水中的波谱建模研究（英文）

This study evaluates the capability of the Simulating WAves Nearshore(SWAN) wave model(version 41.01) in predicting significant wave height and spectral peak energy content for swell waves in very shallow water of surf zone during depth-induced wave breaking and dissipation. The model results were compared with field measurements at five nearshore stations. The results demonstrated that some breaker index formulations were successful for significant wave height prediction in surf zones.However, an incorrect shape of the energy spectrum and overestimated near spectral peak energy content at shallow water stations were obtained using all of the embedded depth-induced wave breaking formulations in SWAN. The dependent breaker index on relative depth(Kpd) formulation, which was successful in predicting near spectral peak energy content, resulted in an average error of 30%. Finally, this formulation was modified to enhance the model performance in reproducing the spectral peak energy content.     

Spectral Wave Modeling in Very Shallow Water at Southern Coast of Caspian Sea

This study evaluates the capability of the Simulating WAves Nearshore (SWAN) wave model (version 41.01) in predicting significant wave height and spectral peak energy content for swell waves in very shallow water of surf zone during depth-induced wave breaking and dissipation. The model results were compared with field measurements at five nearshore stations. The results demonstrated that some breaker index formulations were successful for significant wave height prediction in surf zones. However, an incorrect shape of the energy spectrum and overestimated near spectral peak energy content at shallow water stations were obtained using all of the embedded depth-induced wave breaking formulations in SWAN. The dependent breaker index on relative depth (K_pd) formulation, which was successful in predicting near spectral peak energy content, resulted in an average error of 30%. Finally, this formulation was modified to enhance the model performance in reproducing the spectral peak energy content.     

Virtual hull monitoring of a naval vessel using hindcast data and reconstructed 2-D wave spectra

A novel virtual hull monitoring approach is assessed using full-scale measurements from a naval vessel trial to address two questions. First: Can this technique accurately reproduce stress spectra from measured strains? Second: Are responses calculated using reconstructed two-dimensional wave spectra from hindcast data more accurate than those using simpler wave representations? Stresses calculated using wave hindcast data, ship track information, and stress transfer functions compare favorably to those derived from strain gauge measurements at five structural locations. Wave conditions are represented using a spectrum model along with bulk spectral parameters (significant wave height, peak period, and primary direction) from hindcast datasets and by reconstructing two-dimensional spectra from hindcast partition data. Both approaches give good agreement with strain measurements but using the more-detailed reconstructed two-dimensional wave spectra yields better results. Results suggest that wave hindcast data are sufficient for accurate structural calculations, encouraging further study of virtual hull monitoring using wave hindcast data.     

多功能支持船波浪载荷研究

波浪载荷研究是船舶性能预报和结构安全评估的关键内容。文中利用势流理论直接数值求解多功能支持船遭受的波浪载荷(包括一阶波频力和二阶漂移力),利用统计方法得到波浪载荷的长期预报和短期预报极值,包括波浪总纵弯矩和垂向波浪剪力以用于后续的船舶整体结构安全评估,以及纵向漂移力、横向漂移力和首摇漂移力矩用于船舶的动力定位能力分析中。研究结果表明:求解波浪载荷的势流理论方法精确,能为后续的船舶性能预报和结构安全评估提供可靠的载荷输入。     

不同时间间隔的波浪观测数据对其统计结果的影响

采用不同的波浪观测方法所获得的波浪数据的时间间隔不一致,其数据的准确性须进行分析。基于大埕湾逐时周年波浪观测数据,截取不同时间间隔的波浪数据,采用统计和相关分析法,分析不同波浪数据序列的波况、大浪波高以及周期的相关关系。结果表明,不同时间间隔的波浪资料的波况差异较小,大浪波高差异在11. 4%以内,相关性较好;大浪周期差异在78. 1%以内,相关性较差。时间间隔较长的波高可由本文公式计算得出较精确的数据,在有限资料的情况下为工程应用提供更可靠的波高值。     

基于马尔可夫链的极值波高预测

本文研究了由日最大波高系列估算设计极值波高时，相邻日最大波高间的相关性对极值预测的影响，从日最大波高系列遵从马尔可夫链的假定出发，考虑到国内外经常采用对数一正态分布的韦布尔分布拟合波高长期分布的现实，本文用解析法求解了对数一正态分布情况下的极值预测。同时，对解析法难以求解的非正态随机变量情况（如韦布尔分布），用计算机随机模拟方法求解其极值预测，用上述两种方法对北大西洋和北海有关日最大波高系列的预测