共查询到20条相似文献,搜索用时 171 毫秒
1.
目前,采用随机性分析方法计算不规则波对海洋结构物作用时一般均采用Airy波理论,并未考虑波浪非线性的影响。本文基于二阶Stokes非线性波浪理论探讨了采用非线性波浪理论时随机波浪力谱的计算方法,并用一典型算例,对本文公式的计算结果与线性波理论的计算结果进行比较。计算结果表明,在水深较深时不能忽略波浪非线性的影响。 相似文献
2.
基于三维线性频域势流理论和脉冲响应函数方法计算时延函数与时域波浪力,利用准静定系泊模型来模拟系泊力,利用计算流体力学方法得到粘性阻尼系数,建立了风机在波浪作用下的时域运动方程.论文求解DeepCwind半潜式平台风机的动力响应,计算结果与试验值以及其他数值模拟结果吻合的较好,证明了方法的适用性. 相似文献
3.
基于切片理论的波浪载荷直接计算 总被引:2,自引:0,他引:2
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。 相似文献
4.
间接时域法在无航速浮体波浪上的运动模拟中得到了广泛应用,但其在有航速问题上的适用性没有得到系统论证。论文基于三维移动脉动源得到的频域水动力系数和拉普拉斯方程的线性特性,给出了考虑了航速效应的时延函数。在此基础上重新推导并数值计算验证了有航速条件下附加质量与阻尼系数之间的KK(Kramers-Kronig)关系,统一了有航速浮体和无航速浮体关于水动力系数相互关系的表达。通过讨论波浪力高频、低频部分渐近值得到波浪力脉冲响应函数,采用间接时域法建立六自由度时域运动方程,计算得到浮体运动时历,RAO与频域结果吻合良好。研究证明了间接时域法在处理有航速浮体运动问题上的可行性及其理论上的统一性,同时发现航速效应项对于时延函数计算和运动计算均有重要影响。 相似文献
5.
6.
7.
8.
9.
运用计算软件MATLAB,在规则波作用下,对波浪与两平行垂直薄板之间的作用进行分析,得出二维频域解,同时运用谱分析法确定两平行垂直薄板在不规则波作用下的波浪力结果进行分析比较。 相似文献
10.
《中国造船》2015,(Z1)
骑浪横甩是船舶在波浪中失稳模态之一,其具有较强的非线性且多发生于速度较快的小型船舶上,对其发生界限的研究对于船舶设计与安全运营均具有一定实际意义。论文中提出一种考虑船舶操纵性和耐波性运动耦合的六自由度弱非线性统一模型,对一艘ITTC ship A2渔船尾随浪下的骑浪横甩运动进行时域数值模拟。时域模型中,六自由度耐波性运动辐射绕射力采用切片理论计算,并由脉冲响应函数法转化到时域。非线性回复力和入射波力采用瞬时湿表面压力积分方法计算。操纵性运动基于MMG模型,依据统一理论将操纵性与耐波性运动进行耦合计算。文中应用此模型,对不同航速、波高和GM值下渔船在尾随浪中的运动进行时域模拟。通过分析,将结果分类为周期运动、骑浪横甩造成的倾覆、波浪中失稳造成的倾覆等运动模态,并进一步对各模态间发生的界限进行了探究。 相似文献
11.
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
12.
[Objective]To investigate ship motion and load responses in realistic 3D waves and overcome the limitations of the traditional 2D wave assumption, this paper develops a method for predicting ship motion and load responses in short-crested waves. [Method]The long- and short-term responses of ship motion and load in long- and short-crested waves are numerically predicted using the spectral analysis and statistical probability methods, respectively. The influence of directional function on ship response is also numerically analyzed. Moreover, tank model tests and a large-scale model sea trial are comparatively conducted to validate the difference between ship response and statistics in long- and short-crested irregular waves. [Results]The results show that when navigating against the waves in the same sea condition, the long-crested wave assumption overestimates the statistical mean value of ship load response, but underestimates extreme load in real seas. For long-crested waves, the ship motion and acceleration power spectrum is concentrated around a certain frequency band. [Conclusion]Ship motion and load responses in realistic 3D waves are significantly different from those in 2D long-crested waves. The directional function of short-crested waves also has a significant effect on ship motion and load responses. © 2023 The Author(s). 相似文献
13.
14.
给出了明基床上局部开孔沉箱防波堤在规则波和不规则波作用下反射系数的近似计算方法。将明基床假定为一直立墙,用匹配特征函数展开法给出计算规则波作用下整体结构反射系数的理论解。利用线性传递函数法得到不规则波作用下开孔沉箱防波堤反射波频谱,得到频率平均的反射系数。将反射系数计算结果与已有研究者的试验结果进行了比较,符合良好。 相似文献
15.
16.
17.
基于势流理论和格林函数,探索五体船在不规则波中运动的波浪载荷响应函数,并且运用波谱分析法,采用北大西洋波浪散布图,对船体的几个典型剖面作波浪载荷的长期预报。分析不同航速、不同浪向角下典型剖面上的弯矩和剪力,研究五体船在波浪中运动时剖面载荷的分布规律。 相似文献
18.
Forng-Chen Chiu Wen-Chuan Tiao Jenhwa Guo 《Journal of Marine Science and Technology》2009,14(2):228-239
The present study focuses on the nonlinear behavior of pressure on the hull surface of a high-speed vessel in irregular waves,
particularly the pressure responses of alternately wet and dry areas near the waterline and on the bow zone. The vessel has
high deadrise angles that may be subject to slight impact and water pile-up effects. A series of experiments in regular and
irregular head waves were conducted, and the validity of applying Volterra modeling was investigated. In a previous article
using experimental data in regular waves, it was confirmed that the approximate third-order Volterra model adequately simulated
the variation of pressure responses in regular waves of different steepness up to a wave amplitude with a wavelength ratio
of 0.01, even for the highly nonlinear pressures acting on the abovementioned areas of the hull surface. In this article,
further validation for the second part of the study was obtained using experimental data in irregular waves. The frequency
response functions obtained from the previous study’s experimental data in regular waves were applied to the third-order Volterra
model by combining the input of irregular waves to simulate the responses in irregular waves of sea state five. Then, the
spectra and statistics were analyzed. For the motions, accelerations, and pressure responses in irregular waves (as well as
for the simulated time histories) variance spectra and statistics such as cumulative distributions of peak values and probability
density functions were compared with the experimental results. It was confirmed that even for highly nonlinear and non-Gaussian
pressures on the abovementioned areas of the hull surface, the approximate third-order Volterra model simulates the pressure
responses in irregular head waves up to a sea state of five with adequate accuracy on deterministic and statistical bases. 相似文献
19.
Takashi Tsubogo Koji Masaoka Hiroo Okada Yoshisada Murotsu 《Journal of Marine Science and Technology》1999,4(2):84-92
This paper deals with the dynamic response and strength of very large floating structures (VLFS) in regular and irregular
waves, considering the propagation of the hydroelastic deflection wave of the structure. First, a simplified estimation method
is presented for the dynamic response and strength of the structure in regular waves. Then, the validity of the method is
demonstrated by comparing its results with analytical results and experimental results for a mat-type floating structure model.
Next, a simplified estimation method for dynamic responses under long crested irregular wave conditions is presented by using
the above results and by combining them with irregular sea wave spectra. Finally, the applicability of the method is investigated
through numerical examples carried out for a 4,800-m class VLFS under trial design. Characteristics of the hydroelastic waves,
short-term responses, and reliability levels are numerically identified.
Received for publication on April 14, 1999; accepted on Sept. 10, 1999 相似文献
20.
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