共查询到17条相似文献,搜索用时 46 毫秒
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应用透空壁内流体速度与壁两侧的压力差成正比的线性模型,研究了斜向波与无限多个开孔沉箱的相互作用.依照结构物的几何形状,把整个流域分成无限多个子域,在每个子域内应用特征函数展开法对速度势进行展开.对于沉箱内的波浪运动,引入相位差概念;在构造反射波模型时,考虑了结构物的几何形状影响.列举出物理模型实验结果与数值实验结果的比较,可以看出两者吻合较好.进一步的数值计算验证表明,当孔隙系数无限大时,开孔墙前后的速度非常接近.在低频入射波作用下,垂直于沉箱的水平力随角度的变大而减小,平行于沉箱排列方向的力则变大. 相似文献
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开孔沉箱与斜向波作用的理论研究和实验验证 总被引:2,自引:0,他引:2
应用透空壁内流体速度与壁两侧的压力差成正比的线性模型,研究了无限多个开孔沉箱在斜向波作用下的反射问题。整个流域被分成无限多个子域,在每个子域内应用特征函数展开法对速度势进行展开。对于沉箱内的波浪运动,根据沉箱位置引入相位差概念。在构造反射波模型时,考虑了结构物几何形状周期性的影响。结果表明,当孔隙系数无限大时,开孔墙前后的速度非常接近,反射系数符合能量守恒定律。在低频入射波作用下,沉箱越短,其反射系数越小,反射系数随着角度的变大而减小。 相似文献
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双层局部开孔板沉箱对波浪反射的理论研究 总被引:1,自引:0,他引:1
提出了一种用于研究由双层开孔板和一个不透水后板的开孔结构对斜向波反射率的理论分析方法。整个流域被分成三个子域,在每个子域内应用特征函数展开法以得到该域内包含未知展开系数的势函数的表达式,在速度势的展开中,考虑了非传播模态波浪的影响。通过匹配开孔板处的边界条件可以求解待定的展开系数,继而求解双层开孔板防波堤结构对斜向波的反射率。数值计算结果与试验结果进行了比较,符合较好。并进一步讨论了几个重要因素对反射系数的影响。 相似文献
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开孔沉箱孔洞周围存在以三轴循环应力为特征的复杂承载区,其中混凝土损伤速度远大于单轴应力条件,局部疲劳损伤快速累积使结构整体承载能力迅速下降。考虑迎浪面入射波浪与消浪室内反射波浪的循环作用,针对开孔区域复杂应力状态下的疲劳损伤问题,基于不可逆损伤力学发展的数值计算方法模拟开孔板疲劳过程,得到循环荷载作用下不同类型开孔板的损伤演化历程,并计算损伤后整体结构极限承载力大小,通过综合对比孔洞损伤发展规律和结构极限承载能力,建立了疲劳作用下开孔沉箱极限承载能力判断依据。现有规范依据设计使用年限、波浪条件、作用效应组合等确定材料与结构强度,但并未充分体现开孔结构的优势与承载特点,在此基础上文中补充了开孔结构的优化设计以及实际寿命判断。 相似文献
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1 IntroductionRecently breakwaters with perforated front wallshave been widely used. The use of perforated break-waters mainly has two advantages. Firstly, wave forcesacting on the whole structure can be divided into twoparts on two different walls with a phase difference.To select the distance between the two plates suitably,the total wave force on the whole structure can bemaintained at a low level. Secondly, waves will dissi-pate when they transmit over a porous medium. Thus,the reflection… 相似文献
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The interaction of diagonal waves with perforated-wall breakwater partially filled with rock fill is studied using the linear potential theory. By means of the matched eigenfunction expansion method, an analytical method is presented to calculate the reflection coefficient and the wave force coefficient of the breakwater. The calculated results of the reflection coefficient for limiting cases are the same to the existing results. The main effect factors of the reflection coefficient and the wave force coefficient are analyzed by numerical examples. With the increasing of thickness of rock fill, the wave force coefficient on the perforated wall generally decreases, while the reflection coefficient increases. With the increasing of the incident angle of the wave, the reflection coefficient of the breakwater first decreases, reaches its minimum, and then increases monotonously. 相似文献
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多消浪室局部开孔沉箱防波堤反射特性的迭代解析研究 总被引:1,自引:0,他引:1
基于势流理论,对多消浪室局部开孔沉箱防波堤的反射特性进行解析研究。研究中采用开孔墙处的二次压力损失边界条件,可以直接考虑波高对于开孔墙处能量损失的影响。利用匹配特征函数展开法和迭代方法得到当前问题的解析解。收敛性验证表明,迭代计算和级数解均具有良好的收敛性。该解析解的计算结果与分区边界元的数值计算结果一致,并且与已有的试验结果符合良好。通过算例分析,研究开孔沉箱防波堤反射系数的主要影响因素。结果表明:与单消浪室开孔沉箱防波堤相比,多消浪室开孔沉箱防波堤可以在更宽的波浪频率范围内保持低反射;增大开孔墙的开孔率,有利于降低多消浪室开孔沉箱防波堤的反射系数;当开孔墙的开孔率沿着入射波方向依次递减时,多消浪室开孔沉箱防波堤的反射系数较小。本文所建立的解析模型简单可靠,可用于工程初步设计中分析开孔沉箱防波堤的水动力性能。 相似文献
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In this study, the total horizontal and vertical forces as well as the phase differences of irregular waves on a partially perforated caisson breakwater are investigated. The partially perforated caisson is located on a rubble fill foundation and filled with rock. Based on linear potential theory, a simple semi-analytical solution of the present problem is developed by means of the matched eigenfunction method and the finite element method. Experimental tests are also conducted to validate the theoretical model and examine the wave forces acting on the perforated caisson. The effects of some of the main factors on the total wave forces and the phase difference are examined. Theoretical and experimental studies show that when the total horizontal force reaches its peak, the simultaneous total vertical (upward) force is rather small or even becomes downwards. This is due to the existence of an obvious phase difference between the time histories of the total horizontal and vertical forces, which is an important advantage of perforated caissons over traditional structures. 相似文献
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The reflection coefficient and the total horizontal forces of regular waves acting on theperforated caisson are experimentally investigated. The empirical relationship between reflection coefficient and the ratio of the total horizontal forces acting on the perforated caisson to those on solid vertical walls with the relative chamber width, relative water depth and porosity of perforated wall, etc. are given. Moreover, the results of the ratio of the total horizontal forces are also compared with formulas given by Chinese Harbour Design Criteria and Takahashi, which may be useful for the practical engineering application. 相似文献
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The reflection of regular and irregular waves by a partially perforated caisson breakwater on a step bed 总被引:2,自引:0,他引:2
This study examines the reflection of regular and irregular waves from a partially perforated caisson breakwater located on a step bed. The step bed is treated as an idealized rubble mound foundation. Based on the linear potential theory, an analytical solution is developed to calculate the reflection coefficient of the structure subjected to regular waves. The matched eigenfunction expansion method is used for the solution. The regular wave method is also extended to irregular waves using a linear transfer function. The calculated results obtained for limiting cases are exactly the same as corresponding results given by the previous researchers. The present predictions also agree well with experimental data in the published literatures. Numerical experiments are conducted to examine the variations of the reflection coefficient versus its main effect factors, and some interesting results are presented. 相似文献
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LIU Yong LI Yucheng TENG Bin MA Baolian 《海洋学报(英文版)》2007,26(3):129-141
The reflection of regular and irregular waves from a partially perforated caisson breakwater with a rock-filled core is examined. The present mathematical model is developed by means of the matched eigenfunction method. Numerical results of the present model are compared with the experimental data of different researchers. Numerical examples are given to examine the effect of rock fill on the reflection coefficient. The differences between regular and irregular waves are also investigated by means of theoretical and experimental results. It is found that the minimum reflection coefficient of irregular waves is larger than that of corresponding regular waves, but the contrary is the case for the maximum reflection coefficient. 相似文献