共查询到18条相似文献，搜索用时 562 毫秒
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本文研究了随机波作用下吸能沉箱防波堤的各水动力特性。喷嘴负荷用最小二乘法进行线性处理。用局部有限元法求解流场。理论表明吸能沉箱防堤的吸能效率在不同的有效波周期处均较高,作用在其上的波力亦比传统直立堤的小。 相似文献
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建于本世纪初的吴淞导堤,经数十年的使用,现拟加固,以适应近期上海运输的需要。安放在导堤上的砼方块已经历80a 的天然暴露,留存于堤上的有4516块,为尽量利用这些块体,需对其破坏情况作出检查。通过现场外观评定、钻取砼芯样、超声测量、砼核子密度仪检测及化学分析等手段,对其现在质地作了较系统的检查,并据此作了评估,提出了修复方案,可供修复设计及施工时参考。 相似文献
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淹没矩形防波堤透反射系数特性研究 总被引：2，自引：1，他引：2
采用解析方法研究了斜向入射波作用下淹没矩形防波堤的透反射系数特性.首先利用特征函数展开法导出了绕射势函数的分析解和透反射系数的计算公式,然后利用边界元方法验证了解析解,在此基础上利用解析解分析了若干工况下的防波堤透反射特性.计算结果表明,淹没矩形防波堤截面的宽度、高度和相对位置以及入射角的改变都不同程度影响反射系数和透射系数.在中等深度条件下,对于一定频率的波浪,位置和尺寸适当的淹没矩形堤可以反射大部分斜向入射波.研究结果对设计淹没的矩形防波堤具有重要的参考价值. 相似文献
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应用椭圆余弦波的绕射理论，推导了V形防波堤的浅水波浪绕射解析解，从而对现有的Airy微幅波理论进行了有效拓展。据此理论对V形防波堤的浅水波绕射作用进行了解析计算，并与几何形状相近的圆弧型防波堤结果加以了对比。结果表明：椭圆余弦波理论计算的V形防波堤最大波浪力和最大绕射波面明显大于微幅波理论的对应值。本方法适用于张角180°的有限长直立薄壁防波堤的浅水波绕射作用计算，从而将无限长直立薄壁堤的反射波理论加以有效拓展。张角同为120°的V形堤与圆弧堤的堤后防浪效果相近，而180°圆弧堤的堤后防浪效果优于张角90°的V形堤。 相似文献
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波浪与外壁透空双方形沉箱相互作用 总被引：1，自引：1，他引：0
在线性波浪理论下,利用复合边界元素法(composite BEM)数值解析在等水深、规则波浪入射二种外壁透空双方形沉箱的无因次波力及Kd绕射分布图,并分别与其他研究者所作双圆筒内、外圆柱无因次波力及绕射分布图的计算结果进行比较,都说明本模式的合理性和可行性。在考虑不同透水参数下,分别计算波浪作用在内、外结构物的波力及沉箱四周绕射系数大小分布图。计算结果显示:波浪作用于外壁透空全透水双方形沉箱,外方柱无因次最大波力值会随着透水参数增加而降低;内方柱无因次最大波力值则随着透水参数增加而增加。本研究结果可供设计外海透水方形沉箱结构交互作用参考。 相似文献
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不同结构形式潜堤上的随机波浪运动 总被引：3，自引：0，他引：3
潜堤在海岸保护和促潍保淤中具有重要的意义。工程效益和经济投入受到潜堤结构形式和高度的影响。基于RANS方程和流体体积（VOF）方法的模型，计算不同潜堤上的波浪运动。潜堤形式包括矩形结构、梯形结构、半圆结构和槽形结构。模拟了不规则波越堤时波浪的破碎特征、破波类型以及波高的变化。通过分析流场和波高分布的变化，得到潜堤上波能散耗的规律，并且得出最优潜堤结构形式。讨论了相对堤顶高度、破碎点位置、相对堤顸宽度、波陡和潜堤结构形式等对波能耗散的影响。 相似文献
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本文基于欧拉座标一次近似式,通过不规则波波高的概率分布来推求作用在削角式直墙堤上的波浪压强峰值以及总水平波浪力峰值的概率分布。文中还对不规则波情况下越浪修正系数的形式进行了探讨,并对部分计算结果进行了实验验证。 相似文献
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Analytical and Experimental Studies on Hydrodynamic Performance of Semi-Immersed Jarlan-Type Perforated Breakwaters 总被引：2，自引：1，他引：1
The present study proposes a new semi-immersed Jarlan-type perforated breakwater including a perforated front wall, a solid rear wall, and a horizontal perforated plate connecting the lower tips of the two walls. An analytical solution is developed to estimate the hydrodynamic performance of the new breakwater. The analytical solution is confirmed by solutions for special cases, an independently developed multi-domain boundary element method solution and experimental data. Numerical examples based on the analytical solution indicate that compared with previous semi-immersed breakwaters, the new breakwater may have better wave-absorbing performance and smaller wave forces. Some useful results are presented for practical designs of semi-immersed Jarlan-type perforated breakwaters. 相似文献
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A series of physical tests are conducted to examine the characteristics of the wave loading exerted on circular-front breakwaters by regular waves. It is found that the wave trough instead of wave crest plays a major role in the failure of submerged circular caissons due to seaward sliding. The difference in the behavior of seaward and shoreward horizontal wave forces is explained based on the variations of dynamic pressure with wave parameters. A wave load model is proposed based on a modified first-order solution for the dynamic pressure on submerged circular-front caissons under a wave trough. This wave loading model is very useful for engineering design. Further studies are needed to include model uncertainties in the reliability assessment of the breakwater. 相似文献
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Sliding is one of the principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. Herein, the mass-spring-dashpot model of caisson-base system is used to simulate the vi-brating-sliding motion of the caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave impacts and the sliding motion on the dynamic response behaviors of caisson breakwaters are investigated and the calculation of relevant system parameters is discussed. It is shown that the dynamic responses of the caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. The amplitude of dynamic response of the caisson is lower under single peak impact excitation than that under double peak impact or shock-damping oscillation impact excitation. Though the disp 相似文献
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In the dynamic stability analysis of a caisson breakwater, most of current studies pay attention to the motion characteristics of caisson breakwaters under a single periodical breaking wave excitation. And in the lifetime stability analysis of caisson breakwater, it is assumed that the caisson breakwater suffers storm wave excitation once annually in the design lifetime. However, the number of annual severe storm occurrence is a random variable. In this paper, a series of random waves are generated by the Wen Sheng-chang wave spectrum, and the histories of successive and long-term random wave forces are built up by using the improved Goda wave force model. It is assumed that the number of annual severe storm occurrence is in the Poisson distribution over the 50-year design lifetime, and the history of random wave excitation is generated for each storm by the wave spectrum. The response histories of the caisson breakwater to the random waves over 50-year design lifetime are calculated and taken as a set of samples. On the basis of the Monte Carlo simulation technique, a large number of samples can be obtained, and the probability assessment of the safety of the breakwater during the complete design lifetime is obtained by statistical analysis of a large number of samples. Finally, the procedure of probability assessment of the breakwater safety is illustrated by an example. 相似文献
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基于开源程序REEF3D,通过建立高精度二维数值波浪水槽,系统研究了聚焦波浪在浅堤上传播变形的规律,着重分析了聚焦波浪通过浅堤的水动力过程及能量变化规律,讨论了不同波浪要素对聚焦波浪传播特性的影响。除此之外,还考虑了双浅堤布置对聚焦波浪传播变形的影响。研究结果表明:极端波浪通过浅堤时,堤顶水深越小,波浪主频能量衰减越显著。在给定堤顶水深条件下,聚焦点与浅堤的相对位置对聚焦波浪能量的衰减影响较小。在双浅堤布置条件下,随着浅堤间距的增加,上下游浅堤的相互影响逐渐减弱,高频段的波浪能量也随之减小。 相似文献
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带胸墙斜坡堤越波量的试验研究 总被引：1，自引：0，他引：1
带胸墙斜坡式防波堤堤顶标高的合理确定，有赖于越波量的正确计算。本文基于水力学中流量系数的概念，建立越波量的计算公式。对影响流量系数的几个主要因素：波高、波陡、胸墙高、平台宽度、相对水深和护面结构等，进行了较系统的试验和讨论，提出了确定流量系数的经验公式。另外，还根据越波量的大小及越波波态，将堤分为：不越水堤、少量越水堤、越水堤及半潜堤四类，可作为合理确定堤顶标高时参考。 相似文献