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随机波浪作用下座床式大直径薄壁圆筒防波堤的动力分析空间模型 总被引：1，自引：0，他引：1
随机波浪作用下座床式大直径薄壁圆筒防波堤的动力运动过程分为:摇摆、摇摆—小滑移运动和摇摆—大滑移运动三种运动模态,引入了控制侧向滑移的阻滑板—弹簧—阻尼器运动模型,建立了相应的动力分析空间模型。在大型有限元软件ANSYS中利用参数化设计语言APDL进行二次开发实现其空间模型,并把此空间模型计算结果与文献[1]中建立的平面模型计算结果比较,获得了一些有价值的结论,表明了本模型和方法对随机波浪荷载作用下大直径薄壁圆筒防波堤动力响应的数值模拟的可行性和有效性。 相似文献
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宽肩台堆石堤是海岸工程中的一种海堤形式，其以结构简单、施工快捷、布局灵活和造价经济的特点在工程中得到了广泛应用。宽肩台防波堤以堆积块石为主体，在海区波浪作用下达到稳定的堆积结构。进行宽肩台式防波堤稳定性的研究
是设计宽肩台防波堤的重要基础。介绍了波浪水槽的光滑粒子动力学 （SPH） 理论和建立方法，验证了造波结果。提出了一种块石单元法 （GEM） 模式，以块石单元为独立刚体来模拟宽肩台防波堤上的块石在波浪作用下的受力状态和运动过程。建立了一种垂向二维光滑粒子动力学方法 SPH 与 GEM 耦合的波浪和块石模型，采用 SPH 与 GEM 相结合，对防波堤堆石孔隙外部的波浪运动和内部的孔隙环流进行模拟计算，并根据 Forchheimer 公式确定孔隙内部的压力。用 SPH 方法模拟堆石堤外部流场的波浪破碎压力，用孔隙环流模拟堆石堤内部的孔隙压力。使用耦合模式模拟了宽肩台防波堤孔隙流场，验证了孔隙压力分布。模拟了波浪作用于块石和块石对波浪动力响应过程，给出了静态平衡到动态平衡的流固场变化，模拟结果与物理模型试验结果基本一致。耦合模型的建立为宽肩台堆石堤的稳定性研究提供了理论依据，同时也为同类型工程研究提供了新思路。 相似文献
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回顾了日本防波堤建造的历史，根据波浪力和防波堤稳定性讨论了当今混合式防波堤的设计方法。现在日本的混合式防波堤的设计技术是上来该领域经验和实际研究的鼎盛时期。对于混合式防波堤的绝大部分情况，能够精确地计算出设计波浪力的Ｇｏｄａ公式成了防波堤设计的极好工具，在某些情况下，由于波施于皮波堤上部直墙断面上的冲击压力非常大，因此在进行防波堤设计时必须予以考虑。要采用能够消散波浪力的混凝土块体覆盖在混合式防波 相似文献
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透空格栅板式防波堤是一种新型防波堤结构,为了促进该结构在实际工程中的应用,论文通过模型试验研究其所受波浪点压力和波浪总力的特征。试验结果表明,在规则波作用下,下层水平格栅板所受波浪点压力较上层水平格栅板大,且防波堤中前端波浪点压力分布不规律;相对板宽B/L对该防波堤所受波浪总力的影响较大,相对板间距S/h对其整体稳定性的影响次之,而相对波高H/h主要影响该防波堤的垂向受力;此外,当上层水平格栅板与静水面齐平且孔隙率相对较大时,该防波堤所受波浪总力最小,对其整体稳定性最有利。 相似文献
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针对海工作业平台、海洋养殖网箱等海洋装备的安全防护问题，提出了一种带空气透平的后弯管浮式防波堤，该空气透平既可将作用在防波堤上的波浪能转化成机械能并用于发电，还可显著减小防波堤的锚链力。在介绍了防波堤原理和结构特点的基础上，设计了物理实验模型，并在实验室造波池内进行了模型试验，研究了波浪周期、波高、吃水深度与弯管数量等因素对后弯管浮式防波堤透射系数和锚链力的影响规律。研究结果表明，波浪周期越短，波高越低，防波堤的透射系数越小，锚
链力越小，其消波性能优于传统的浮式防波堤. 相似文献
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浮式防波堤充分利用波能在水深方向的分布特性,在满足工程消浪要求的同时对海域水沙交换影响较小,且能够快速布置,在某些实际工程有一定应用前景。为了深入了解波浪作用下浮式防波堤的动力响应,基于OpenFOAM标准求解器olaFlow,在刚体运动求解计算中植入锚链求解模块MOODY(mooring cable dynamics),实现了基于重叠网格方法的浮体运动与锚链受力耦合求解,建立了锚链系泊浮式防波堤动力响应的二维数值模型。利用该数值模型对锚链系泊单方箱浮式防波堤在波浪作用下的透射系数、运动响应、锚链张力进行了模拟,并和相关试验结果进行了比较。结果表明,模型能够准确模拟二维波浪和浮式防波堤的相互作用,并用于三维模型的改进。 相似文献
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透空式防波堤周围的非线性波浪传播的数值模拟 总被引：1，自引：0，他引：1
对非线形波浪在透空式防波堤周围的波浪变形进行了数值模拟,在Boussinesq波浪方程中加入与透空建筑物有关的新的耗散项,从而界定了透空建筑物引起的部分反射和透射,波浪折射衍射的传播过程通过控制方程求解。波浪控制方程通过有限差分方法求解。模型应用于模拟波浪经过具有部分反射的群桩式透空结构,结果表明透空式防波堤可以有效地衰减波浪,是重力式结构的一种替代形式。 相似文献
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基于粘性流模型的筒型基础防波堤波浪力数值分析 总被引：3，自引：0，他引：3
筒型基础防波堤是一种新型港口海岸工程结构,其基础上部是由连续排列的圆筒构成的直立防浪墙.采用粘性流数值模型,研究连续圆筒防波堤上波浪力竖向分布、水平(沿圆筒环向)分布和波浪力合力特性,并对粘性流数值模型计算的平面直墙波浪力与海港水文规范方法计算结果;粘性流数值模型计算的连续圆筒墙面波浪力与平面直墙波浪力;无限长连续圆筒墙面波浪力与有限长连续圆筒墙面波浪力进行比较分析.针对所选工程算例,建议按<海港水文规范>中平面直墙波浪力计算方法确定连续圆筒防波堤上的波浪力时,波峰时考虑0.90左右的折减系数,波谷时考虑0.95左右的折减系数. 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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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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It is assumed that the storm wave takes place once a year during the design period, and N histories of storm waves are generated on the basis of wave spectrum corresponding to the N-year design period. The responses of the breakwater to the N histories of storm waves in the N-year design period are calculated by mass-spring-dashpot mode and taken as a set of samples. The failure probability of caisson breakwaters during the design period of N years is obtained by the statistical analysis of many sets of samples. It is the key issue to improve the efficiency of the common Monte Carlo simulation method in the failure probability estimation of caisson breakwaters in the complete life cycle. In this paper, the kernel method of importance sampling, which can greatly increase the efficiency of failure probability calculation of caisson breakwaters, is proposed to estimate the failure probability of caisson breakwaters in the complete life cycle. The effectiveness of the kernel method is investigated by an example. It is indicated that the calculation efficiency of the kernel method is over 10 times the common Monte Carlo simulation method. 相似文献
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It is assumed that the storm wave takes place once a year during the design period, and N histories of storm waves are generated on the basis of wave spectrum corresponding to the N-year design period. The responses of the breakwater to the N histories of storm waves in the N-year design period are calculated by mass-spring-dashpot mode and taken as a set of samples. The failure probability of caisson breakwaters during the design period of N years is obtained by the statistical analysis of many sets of samples. It is the key issue to improve the efficiency of the common Monte Carlo simulation method in the failure probability estimation of caisson breakwaters in the complete life cycle. In this paper, the kernel method of importance sampling, which can greatly increase the efficiency of failure probability calculation of caisson breakwaters, is proposed to estimate the failure probability of caisson breakwaters in the complete life cycle. The effectiveness of the kernel method is investigated by an example. It is indicated that the calculation efficiency of the kernel method is over 10 times the common Monte Carlo simulation method. 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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1 .IntroductionInrecent years ,especiallyfrom1994 when aninternational conference on breakwater design washeldinJapan,muchresearchonthe dynamic analysis of caisson breakwaters has been done ,and manyimportant progresses have been made .Oumeraci and Korten… 相似文献
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通过测试一系列不规则波工况研究了防浪建筑物存在下珊瑚礁海岸附近短波、低频长波和增水的变化规律，并对比了防浪建筑物的不同位置情况。分析结果表明：波浪在沿礁传播过程中，短波波高沿礁坪持续衰减，低频长波波高沿礁坪逐渐增大，波浪增水则沿礁坪基本保持不变；海岸附近短波随着防浪建筑物与礁缘距离的变大而减小，低频长波则在防浪建筑物处于礁坪后部时达到最大，防浪建筑物位置的变化对于礁坪波浪增水的影响可以忽略。通过理论分析证明了珊瑚礁地形上低频长波是由于群波破碎造成的破碎点移动而产生的；当特定波况作用于特定位置的防浪建筑物时，低频长波在礁坪上会发生一阶共振效应导致其能量在海岸附近达到最大值。 相似文献
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WANG Yuanzhan 《中国海洋工程》2001,(2):205-216
The possible motions of a caisson breakwater under dynamic load excitation include vibrating, vibrating-sliding and vibrating-rocking motions. The models of vibrating motion and vibrating-sliding motion have been proposed in an early paper. In this paper, a model of vibrating-rocking motion of caisson breakwaters under breaking wave impact is presented, which can be used to simulate the histories of vibrating-rocking motion of caisson breakwaters. The effect of rocking motion on the displacement, rotation, sliding force and overturning moment of breakwaters is investigated. In case the overturning moment exceeds the stability moment of a caisson, the caisson may only rock. The caisson overturns only in case the rocking angle exceeds the critical angle. It is shown that the sliding force and overturning moment of breakwaters can be reduced effectively due to the rocking motion. It is proposed that some rocking motion should be allowed in breakwater design. 相似文献
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A numerical model is presented for the prediction of the wave field due to the diffraction of directional random waves in a harbor of arbitrary shape with partially reflecting boundaries. The water depth is assumed uniform and the method is based upon the superposition of diffraction solutions for monochromatic waves obtained by a two-dimensional boundary integral equation approach. The incident wave conditions are specified using a discrete form of the Mitsuyasu directional spectrum. The present numerical model has been validated through comparisons with previous experimental data and theoretical results for both regular and random wave diffraction by offshore breakwaters and in harbors. Good agreement was obtained in all cases. Based on these comparisons it is concluded that the present numerical model is an accurate and efficient tool to predict the wave field inside a harbor or around a breakwater in many practical applications. 相似文献