共查询到19条相似文献,搜索用时 218 毫秒
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任赵飞王科华张军李伟仪 《港工技术》2022,(5):1-5
本文结合菲律宾马尼拉湾某项目,采用两种理论分布快速选型方法,即偏度系数Cs与峰度系数Ck相对关系快速选型方法和K-S检验/A-D检验快速选型方法,进行理论分布选型的定量分析和极值风速拟合分析。两种方法优选推荐的理论分布函数基本一致,不同理论分布对同一组样本的拟合度存在一定差异,实际应用中建议双向验证,从而选出最适合样本的理论分布。采用不同推荐理论分布计算得到极值基本一致,结合国内外规范对极值风速理论分布的介绍,建议理论分布的选择,应以拟合最佳为原则进行选配,同时要确定外推值的置信区间。所得成果可为类似水文设计参数分析提供参考。 相似文献
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研发一型采用“泵进流出”开式循环水养殖系统的养殖平台,通过海水泵将外界环境海水抽进养殖舱内,在养殖舱底部设置开孔将舱内养殖尾水自然排出,养殖舱始终与外界海水保持联通,内外液面持平且需要考虑自由液面对稳性的不利影响。针对在平台的完整稳性和破损稳性计算校核中实际反映开式养殖水舱与外界海水联通且考虑大面积自由液面的特点,结合现行规范的具体要求和浮体稳性原理进行分析,应用NAPA软件进行不同模式组合的计算验证,结果表明,完整稳性和确定性破损稳性中推荐采用考虑养殖舱浮力的计算模型,概率性破损稳性中推荐采用扣除养殖舱浮力的计算模型。 相似文献
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为求得充分反映长江口水域渡浪特征的特定波谱,对该水域波浪谱进行细致分析,选用PM谱、新规范谱(海大谱)、J谱(JONSWAP谱)拟合实测谱,估算3种谱型的参数,并将谱参数与特征波要素进行比较,确定它们之间的关系.最后根据拟合结果提出不同范围的推荐谱型,建议在1.27<p<6.77时采用海大谱,p不在上述范围内时采用J型谱. 相似文献
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水中气泡幕的多体多次声散射模型分析 总被引:1,自引:1,他引:0
通过引入水中气泡群分布函数,建立了气幕多体多次声散射模型.与多体一次散射模型相比,多体多次声散射模型能够更加真实地反映出具有较高体积浓度气幕的声散射特性,因此,它是分析声波在气幕介质中反射和透射问题的重要基础. 相似文献
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To ensure hull structural strength of container ships in association with their increase in size, it is very important to grasp the hull stress histories all over the hull structure in actual sea state. However, ordinary hull stress monitoring systems are insufficient for this purpose because of the small number of stress sensors actually practicable. Therefore, in this paper, we discuss an approach to reproduce the hull stress responses which are not measured based on the estimated wave spectrum from the limited measurement data. To achieve this, we introduce a new model to estimate directional wave spectra based on measured ship stress responses and ship response functions, and further we estimate other ship responses using the model. To model an arbitrarily shaped directional wave distribution, the 360° direction is discretized into 36 directions of 10-degree intervals instead of using a directional distribution function, and in each direction, the wave spectrum is represented using the Ochi (3P) spectrum with three parameters (average wave period, significant wave height, and kurtosis). The authors discuss the evaluation results based on two stress response combinations, and a comparison is made between the sea state estimates made by the proposed method and the ocean wave hindcast database (JWA). Furthermore, by comparing the significant values and the spectra of the measured response of the ship with the estimated response based on both the estimated sea state by the proposed method and the hindcast sea state, the accuracies of the proposed method and the hindcast method are discussed in terms of ship stress estimation at non-instrumented locations. 相似文献
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用C语言和汇编语言编制了蛇形造波机的控制和数据处理程序,用于生成规则波、斜向规则波、不规则波、斜向不规则波和多方向不规则波。介绍了驱动信号的生成、采样间隔的确定、方向函数的估计和方向谱的修正方法。 相似文献
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针对数学模型很少能较好地模拟天然海浪的多向性、不规则性的特点,基于港口波浪整体物理模型试验,对不规则波作用下港域内测点的波高扰动系数的分布规律进行研究。结果表明:在绕射作用为主的掩护区域,多向波的绕射性能大于单向波,波浪扰动系数较大;波浪绕射、反射作用均十分强烈的掩护区域,多向不规则波与单向不规则波的扰动系数看不出明显的大小关系。以反射作用为主的掩护良好区域,单向不规则波的扰动系数较多向不规则波的要大,且受反射作用越大的区域,单向波的扰动系数大的越多。在以绕射作用为主的掩护区域,波浪分布对周期的敏感性较差;在以反射作用为主的掩护良好区域,波高分布对周期的敏感性较强。在绕射、反射都较强的情况下有可能单向波作用下的港内波高大于单向波,用单向不规则波来模拟反而是偏安全的。在进行港内波况整体模型试验时需要根据实际的工程条件做出综合考虑来决定波型,必要时要对单向、多向不规则波都要进行试验以确定最佳方案。 相似文献
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《Marine Structures》2006,19(1):33-69
In general, two main concepts can be applied to estimate the on-site directional wave spectrum on the basis of ship response measurements: (1) a parametric method which assumes the wave spectrum to be composed by parameterised wave spectra; or (2) a non-parametric method where the directional wave spectrum is found directly as the values in a completely discretised frequency-directional domain without a priori assumptions on the spectrum. The paper outlines the theory of these two concepts, and it is shown how to deal with the speed-of-advance problem for operating ships. In addition, the methods include an equivalence of energy in the governing equations and, as regards the parametric concept, a frequency-dependent spreading of the waves is introduced.The paper includes an extensive analysis of full-scale measurements for which the directional wave spectra are estimated by the two ship response-based methods. Hence, comparisons are made between these estimates and, moreover, the agreement with the corresponding directional wave spectra produced by the wave radar system WAVEX is studied. The agreement between the two methods is reasonable, as well is the agreement between the results of these methods and those of WAVEX. It is difficult to propose one of the ship response-based methods in favour of the other, since they perform equally well. 相似文献