浮筒的波浪力计算

本文研究了浮筒在漂浮状态时波浪力的计算方法，导出了考虑有限波幅影响的波浪力计算公式。为了验证本公式的可靠性，对５００吨浮筒模型在上海交通大学船池中进行了模型试验     

计算孤立小桩柱上随机波浪力的一个线性的Morison公式

本文在线性波理论下，从计算孤立小桩柱上随机波浪力的Ｍｏｒｉｓｏｎ公式出发，通过对波浪力的概率密度的推导和分析，提出了一个新的线性化的Ｍｏｒｉｓｏｎ公式，该公式与已在工程上广泛使用的Ｂｏｒｇｍａｎ１９６７年提出的线性化的Ｍｏｒｉｓｏｎ公式在对照力的线性化上略有不同，由这个公式计算的小桩柱上的阻力是按Ｂｏｒｇｍａｎ线性化的Ｍｏｒｉｓｏｎ公式进行计算所得结果的１．０８倍，但按这个新的线性化的Ｍｏｒｉｓｏ     

计算孤立小桩柱上随机波浪力的一个线性化的Morison公式

本文在线性波理论下，从计算孤立小桩柱上随机波浪力的Ｍｏｒｉｓｏｎ公式出发，通过对波浪力的概率密度的推导和分析，提出了一个新的线性化的Ｍｏｒｉｓｏｎ公嵤健８霉接胍言诠こ躺瞎惴菏褂玫模拢铮颍纾恚幔睿保梗叮纺晏岢龅南咝曰模停铮颍椋螅铮罟綅在对阻力的线性化上略有不同，由这个公式计算的小桩柱上的阻力是按Ｂｏｒｇｍａｎ线嵭曰模停铮颍椋螅铮罟浇屑扑闼媒峁模保埃副叮凑飧鲂碌南咝曰模停铮颍椋螅铮顛公式计算的随机波浪力的方差与直接利用Ｍｏｒｉｓｏｎ公式进行计算的结果是完全相同嵉模闹懈龅睦砺鄯治龊褪导扑憬峁砻鳎旱弊枇ο灾保晌颐翘岢龅募埃拢铮颍纾恚幔罡龅南咝曰模停铮颍椋螅铮罟降玫降男∽闲±刍怕氏碌乃婊ɡ藣力，均比直接由Ｍｏｒｉｓｏｎ公式进行计算得到的结果偏小，但按我们给出的线牲化的崳停铮颍椋螅铮罟降玫降慕峁劝矗拢铮颍纾恚幔畹南咝曰模停铮颍椋螅铮罟降玫降慕峁鼚接近于直接由Ｍｏｒｉｓｏｎ公式给出的结果。     

海底边坡稳定性分析中波浪力的求解

针对浅水区波浪的非线性特性,提出了在海底边坡稳定性分析中应用椭圆余弦波理论来研究波浪力的问题,利用非线性弥散关系建立了新的适用于整个水深范围的椭圆余弦波的近似求解方法.结合工程实例,确立了海底边坡波浪力的计算步骤,并编制了计算程序.     

近底管线上的波浪力

本文利用物理模型试验,同步测试了近水底管线在波浪作用下的水平力和外力,并应用莫里逊公式、二阶斯托克斯波理论,按最小二乘原理统计了水平力系数C_D和C_M,分析了它们与KC数间的关系,提出了经验式。本文重点探讨了升力过程线的计算模式,采用傅氏级数法分析了实测升力过程线,提出了五阶升力系数及其相应的初相位值与KC数的经验关系式,从而,首次提出了计算升力和合力过程线的方法。文中还通过实例,比较了力过程线的实测值和计算值,讨论了最大合力值及其相位特征等。     

作用于小尺度方柱上的正向波浪力

基于扩展的Morison方程和实验研究,深入分析了方柱在波浪(规则波及随机波)与水流场中的正向力受力特性,并对其水动力系数C_d及C_m随KC数和方柱迎浪方向变化的关系进行了详细的探讨,有关成果对工程实际有参考价值。     

浮式防波堤非线性波浪力实验研究

对浮式防波堤在不同吃水深度、周期、波高和入射波波型情况，进行了波浪对浮式防波堤非线性作用力的研究，给出了有关实验结果。实验结果表明波浪力在周期较大时，随着波高的增加，出现一阶力减小、高阶力增大的强非线性现象。实验中出现了二阶力大于一阶力的现象，也出现了三阶力大于二阶力和一阶力的现象。     

非线性波浪作用下埋置管道上波浪力简化计算

由于浅水区波浪的非线性影响显著,浅埋管道受非线性波浪荷载的影响大,为了保证管道长期运行的稳定性,在管道设计过程中需要充分考虑由非线性波浪引起的波浪力。考虑孔隙水和海床土的压缩性,基于Biot固结理论和一阶近似椭圆余弦波理论,利用分离变量法推导了非线性波浪作用下浅水区埋置管道周围海床的渗流压力,进而给出了埋置管道上的波浪力压力解析解,并与已有的文献结果进行比较。计算结果表明,在椭圆余弦波的作用下,海底管道周围海床内的渗流压力呈正弦分布,且管道所受的波浪力随着管径的增大而增大。     

聚焦波作用下立柱高阶波浪力特性研究

以方形立柱作为研究对象,对其在聚焦波作用下的波浪力特性进行研究。研究主要基于计算流体力学数值方法,对聚焦波作用下方形立柱在固定、单自由度纵荡、单自由度垂荡三种运动状态下所受波浪力进行研究。利用phase-inversion逆相位分解方法对其高阶力特性进行分析。首先对聚焦波生成方法、数值计算方法与参数设置进行简要介绍,其次展示了三种运动状态下立柱在聚焦波作用下所受波浪力,并对其进行分析,最后利用phase-inversion逆相位分解方法获得高阶波浪力成分并对其载荷特性进行分析讨论。研究发现逆相位分解方法可以有效分离波浪力高阶成分,不同运动状态下立柱所受波浪力会有显著不同。     

双色入射波下二阶波浪力响应函数

应用边界元方法,对双频入射波在和频及差频下的二阶速度势做了完整的求解,通过物面积分计算了任意三维结构上的二阶波浪力的传递函数.对简单几何物体,与发表的结果做了对比,两者吻合良好,验证了本方法的正确性.应用这一方法还对复杂的张力腿平台模型做了实际计算,发现在低频和高频区二阶波浪力平方响应函数有着显著的能量分布.     

随机波浪中畸形波在三维岛礁地形上的试验研究

在试验水池中,开展了波浪在岛礁地形上演化问题的研究。首先在实验水池中建立了西太平洋某岛礁地形的模型,然后采用改进的JONSWAP谱,由造波机产生不同周期、波高的随机波浪。试验中观察到了不同类型畸形波生成的过程及不同波面形态的畸形波。对偏度、峰度及水深与畸形波要素H_m/H_s（H_m表示波列中的最大波高, H_s为有效波高）的关系进行了详细的分析,同时,对畸形波波高H_fr与偏度的关也进行了分析。通过对试验结果分析,发现峰度与畸形波要素i>H_m/H_s呈正相关, H_fr增大时相应的偏度也会呈现增大的趋势。此外,水深的变化剧烈时（如斜坡、海山位置）有助于畸形波的发生。     

Measurements of higher harmonic wave forces on a vertical truncated circular cylinder

Wave forces on a vertical truncated circular cylinder in Stokes waves with the wave slopes ranging from 0.06 to 0.24, are measured in a wave tank. The higher harmonic wave forces are compared with the available values from theories of the FNV (Faltisen–Newman–Vinje) model and Varyani solution. The first harmonic horizontal forces measured are much larger than the theoretical values from the FNV model, while the first harmonic vertical forces are well predicted by the Varyani theory. It was also found that the FNV model significantly overpredicts the second harmonic horizontal forces in high frequency waves, but under predicts the third harmonic forces. The differences between the actual measurement and the theory, in the second and third harmonic horizontal forces, become smaller at low wave frequencies as the wave slope increases. In addition, the transverse instabilities in the incoming waves with high wave slope were observed, which is due to the nonlinear modulation. Measurements were, thus, carried out before the instability occurred.     

Statistics of wave forces on large horizontal cylinders

To the first order in a Stokes expansion, the pressure force exerted by a sea state on a large horizontal cylinder represents a stationary random Gaussian process. A relationship is obtained between the spectrum of this process and the wave spectrum. As a consequence, the basic statistical properties of the height and period of the individual waves of the force-process are also obtained. It is proven that these statistical properties agree very well with the data from a small scale field experiment.     

Effects of Wave Breaking on Freak Wave Generation in Ramdom Wave Train

The experimental studies of the wave breaking effects on freak wave generation are presented within a finite-depth random wave train in a laboratory wave tank. The main attention is paid to the abnormal index, AI=Hmax/Hs, being used to characterize the freak waves, and the changes of the coefficient due to wave breaking. The results show that the occurence in deep water is larger than that in shallow water.     

浅浸没水平圆柱浮子波浪力计算研究

以海漂垃圾收集装置浮式围栏的圆柱浮子为研究对象,基于圆柱浮子的浅浸没特性,改进了Morison方程,并结合物理模型试验,对波浪与浅浸没水平圆柱浮子作用问题进行探讨。结果表明,改进的Morison方程可对水平圆柱浮子的波浪力做精确预测,并揭示了波幅、浸没深度以及周期对圆柱浮子波浪力的影响规律。对于浅浸没的圆柱浮子,所受水平波浪力随波高的增大而增大,随周期的增大而衰减到某一特定值。波浪力的正向大小分布要大于负向,而正负向大小的差异主要受浸没深度的影响。     

Analytical approximate wave form for asymmetric waves

A simple analytical formulation that reproduces a skewed, nonlinear near-bed wave orbital velocity is presented. It contains four free parameters, where two are solely related to the velocity and acceleration skewnesses. The equation is compared with other models and is validated against field and laboratory experiments. The results reveal that it can simulate a wide range of nonlinear wave shapes, reproducing satisfactorily the measured nonlinear wave particle velocity. Also, the new expression overcomes some limitations of the other models. The new formulation is therefore capable of being used in many engineering applications that require the use of representative wave forms.     

Effects of Wave Breaking on Freak Wave Generation in Random Wave Train

The experimental studies of the wave breaking effects on freak wave generation are presented within a finite-depth random wave train in a laboratory wave tank. The main attention is paid to the abnormal index,AI=Hmax/Hs,being used to characterize the freak waves,and the changes of the coefficient due to wave breaking. The results show that the occurrence probability of freak wave events in non-breaking waves is much larger than that in breaking waves and such occurrence in deep water is larger than that in ...     

流体动力干扰对桩柱矩阵阵列波浪力的影响

随着超大型海洋结构物的设计和研究日益受到重视,研究多物体之间的流体动力干扰特性显得十分必要。用波动源在截面周线上分布的方法,就垂直桩柱间三维流体动力干扰对波浪力的影响进行了系统的研究,不仅可得到单行柱列的流体动力干扰力学机理的新特性,而且对多行桩柱阵列的研究也取得了若干新的发现：多行柱柱阵列的遮蔽作用强于单行的;无论是单行还是多行柱列,其流体动力干扰特性存在一个十分敏感的来波频域,在此区域内,力的幅值会大大超过其他频域的受力,而且桩柱阵列与交错阵列的力学特性也有所不同。这对超大型海洋结构物的设计有着重要的指导意义。     

Nonlinear wave interaction with a vertical circular cylinder: wave forces

Second-order wave forces on a large diameter vertical circular cylinder, computed according to a semi-analytic nonlinear diffraction theory, are compared to results of 22 laboratory experiments with regular waves. In general, predicted forces agree quite well with measured forces. In most tests, both measured and predicted maximum forces exceeded linear theory by 5 to 15%. In a few cases, however, the measured forces were less than those predicted by linear theory, in contrast to the second-order predictions. It is shown that these results are related to the phasing of various linear and nonlinear wave force components, and are consistent with those obtained by other investigators.