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为合理确定防浪建筑物的越浪量,基于含非静水压力梯度项的非线性浅水方程建立了近岸波浪越浪数值模型。通过采用域内造波、消波并结合波前静压假定的破碎模型,模拟了规则波和不规则波在斜坡上的波浪传播变形,并在此基础上进行了越浪量数值计算。数值计算结果与物理模型实验结果表明,非静压模型可合理地描述波浪破碎点位置、破碎后的波高、增减水以及斜坡上的堤后越浪量。数值模型具有较高的计算精度和计算效率,可为实际工程防浪建筑物越浪以及堤顶高程的设计提供一种新的数值研究手段。 相似文献
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水波数值模拟一直是水利、海岸、海洋工程和物理海洋等学科关注的重要研究领域之一。在诸多的水波模型之中,非静压水波模型以其计算精度和效率较为平衡的特点受到青睐。非静压水波模型经过近三十年的发展,为科学研究、工程设计分析和海洋资源开发等提供了重要的技术手段。然而,如何开发更为高效的非静压模型,拓宽模型的应用领域一直是研究的主要研究方向。文章综述了非静压模型概念的提出以及数值开发的难点,介绍了非静压模型在波浪传播演化和波浪与结构物相互作用这两方面的应用进展,将有助于研究者了解非静压水波模型的研究和应用现状。 相似文献
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非静压波浪模型是一种近年来得到迅速发展且有望在工程计算中获得广泛应用的波浪模型。为了在非静压波浪模型中实现无反射造波,在连续性方程中添加了质量源项进行域内源造波,并采用阻尼消波方法进行数值消波。数值算例结果表明,所建立的无反射造波方法可以较好地避免非静压波浪数学模型中的二次反射,实现长时间稳定波浪模拟。 相似文献
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区域尺度精细化水动力数值模拟是解决大量工程、地质、环境等问题的重要手段。水动力荷载的直接冲击是近海近岸结构物、设施破坏的主要动力因素。本文章旨在介绍Boussinesq-GreenNaghdi有旋非静压水动力模型及其在区域尺度灾害性海浪的非静压水动力荷载分析和风险分布评价上的应用。这套模型利用了Boussinesq量纲和Green-Naghdi加权积分的结构。速度和压力被用多项式假设来表达和非线性重排法的应用,有效地提高了模型性能,避免了无旋假设的使用,更好地模拟计算了右旋流速和非静态压力场等复杂水动力参数。模拟重现美国和菲律宾沿海台风浪过程,深入分析非静压海浪荷载作用机理,计算海浪荷载的时空分布,与巨石迁移和结构物损坏的调查数据进行对比验证,构建海浪荷载与区域结构物破坏程度分布的相关性,量化各项影响要素如流速、浪高、结构物特征等的风险权重,通过回归分析法推导基于多影响要素的区域海浪风险参数化定量评价方法。为非静压相位解析有旋水动力理论和海浪灾害机理的科学探索提供原创性基础。为沿海人类活动、区域规划、工程设计、防灾减灾等提供科学指导。 相似文献
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高准确度压力测深技术的研究（二） 总被引：1，自引：0，他引：1
四、几个深度压力计算公式的讨论 (一)静压力计算公式(A、C普罗卡娅) 由于海水具有压缩性和斜压性,所以静压和深度间的关系相当复杂。 相似文献
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研究大陆架上的风海流,必须同时考虑海面坡度和海底地形(变水深)的影响。要想获得分析解是比较困难的。 作为对大陆架地形的一级近似,本文考虑线性变化的倾斜海底,岸边水深为零。并假定海岸线平行于地球经度线,考虑柯氏参数随纬度的变化,把这个β效应项——βy作为小参数,同时假定定常两维风场随纬度也是按小参数βy变化着。 相似文献
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本文提出如下假定:(1)波峰处的流向代表波向(滤掉潮流和余流)。(2)波形在测点附近不变形。(3)每个单个波均遵循波的弥散关系。在上述假定前提下,提出一种推算方向谱的新途径,即利用一定点的波面记录和流向记录来推算方向谱的方法。并以某一定点的一次风浪现实记录和给定的两种流向类型作了计算,认为采用这种方法求方向谱是可行的。 相似文献
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海洋粉质粘土在波浪荷载作用后的不排水抗剪强度衰化特性 总被引：3，自引：0，他引：3
通过对南海重塑粉质粘土土样的大量动三轴试验结果分析,得到此种土在波浪荷载作用后不捧水抗剪强度衰化同动载作用引起的动应变幅及平均累积孔压之间的相互关系和预估公式;并通过与超固结土样的静三轴剪切试验结果的比较,发现动、静三轴两种试验结果具有很好的吻合关系。建议可用超固结土样的静三轴剪切试验同时结合部分动三轴试验来预估土样在波浪荷载作用后不排水抗剪强度衰化与平均累积孔压之间的关系。 相似文献
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Coastal protection is proposed to be made out of a contiguous caisson type of wall. These caissons can be designed to resist both lateral static and cyclic loading. With adequate depth of embedment, the walls can be designed to offer significant lateral passive resistance to counteract the lateral static and cyclic loading arising out of wave action. This article describes a set of laboratory tests on model caissons embedded into soft marine clay with different embedment depths. Specially designed earth pressure cells are embedded into the caisson at different depths. A pneumatic system was used to apply lateral static and cyclic loading. Test beds were prepared conforming to soft clay conditions in a test tank of appropriate size. The test results reveal that with this type of arrangement the variation in earth pressure with depth can be conveniently established. The earth pressure developed is related to the lateral load applied. The depth at which the maximum earth pressure occurs is same for both static and cyclic loading. Further, under cyclic loading there is no failure encountered even under cyclic loading level corresponding to 0.9 times the ultimate static lateral capacity. 相似文献
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长江口粘性泥沙在流动盐水中的沉降速度 总被引：1，自引：0，他引：1
本文报道了粘性泥沙在流动盐水中的沉降试验,计算了衰减系数、沉降速度。试验结果表明,粘性泥沙的动水絮凝沉速与静水絮凝沉速相比,前者要此后者小得多。本文的结论对长江口工程规划、设计及环境评价等均有参考价值。 相似文献
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结合模型试验和数值计算对大潜深、带大开口的球形耐压结构静态力学性能进行了研究。研究中考虑到材料非线性、非弹性的因素,通过对材料拉伸试验曲线的分析,得到了材料应力-应变的近似表达式;并且利用超声测厚仪对结构模型的几何缺陷进行了测量。同时基于参数化设计语言建立了有随机几何缺陷的有限元模型,并利用接触单元考虑了大开口观察窗与耐压结构的联系。试验验证表明论文提出的利用有限元软件分析大潜深、大开口耐压壳体力学性能的计算方法和计算策略是准确可靠的,所获得的结果可供设计使用。 相似文献
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Experiments were made on plain concrete subjected to triaxial static loading and constant-amphtude compressive fatigue loading with a constant lateral pressure in two directions. The initial confining pressure was O, O. lfc, O. 25fc and O. 4fc, respectively, for the static test, and O. lfc and O. 25fc for the fatigue test. Based on the triaxial compressive constitutive behavior of concrete, the inflexion of confining pressure evolution was chosen to be the fatigue damage criterion during the test. The rule of evolution of longitudinal maximum and minimum strains, longitudinal cyclic modulus and damage were recorded and analyzed. According to the Fardis-Chen criterion model and the concept of equivalent fatigue life and equivalent stress level, a unified S-N curve for multi-axial compressive fatigue loading was proposed. Thus, the fatigue strength factors for different fatigue loading cases can be obtained. The present investigation provides information for the fatigue design of concrete structures. 相似文献
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Foundations of offshore structures are designed to withstand a combination of static and cyclic loads due to ocean waves. Wave action on offshore structures can cause a significant amount of cyclic horizontal and vertical forces to be transmitted to the soil through the foundation. In all these cases, these cyclic loads are considered to be superimposed over the initial sustained static stress due to the self-weight of structures. This study considers various factors that influence the development of deformation and pore water pressure in a typical cemented marine clay. These results show that the sustained static shear stress significantly influences the strength and deformation behavior of marine clay under cyclic loading. Up to a certain range of sustained static stress, there is an improvement in strength during cyclic loading and the cyclic strains are greatly reduced. 相似文献
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Foundations of offshore structures are designed to withstand a combination of static and cyclic loads due to ocean waves. Wave action on offshore structures can cause a significant amount of cyclic horizontal and vertical forces to be transmitted to the soil through the foundation. In all these cases, these cyclic loads are considered to be superimposed over the initial sustained static stress due to the self-weight of structures. This study considers various factors that influence the development of deformation and pore water pressure in a typical cemented marine clay. These results show that the sustained static shear stress significantly influences the strength and deformation behavior of marine clay under cyclic loading. Up to a certain range of sustained static stress, there is an improvement in strength during cyclic loading and the cyclic strains are greatly reduced. 相似文献
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By using occanographic data (luring 1955-1978, we have analysed aspects of volume transport variation of the Kuroshio tor PN-linc in the East China Sea, and relationships between volume transport variation of the Kuroshio and the subtropical high pressure (SHP) of the Pacific. We have found that volume transport of the Kuroshio is closely related to the long-period oscillations of the subtropical high pressure for 8-9 years and 2-3 years, respectively. The subtropical high pressure has a phase lag behind compared with volume transport of the Kuroshio. In addition, the seasonal volume transport of the Kuroshio is closely related to the subtropical high pressure, too. The results show that volume transport variation of the Kuroshio has certain influence on future variation of the subtropical high pressure. Therefore, the volume transport of the Kuroshio may be an important parameter lor long-period forecasting of the subtropical high pressure. 相似文献
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Luis A. Godoy 《Applied Ocean Research》1985,7(3):152-157
Forced vibrations of the walls of a vertical cylindrical shell under the impact of a breaking wave are studied theoretically. The wave action is modelled as a pressure distribution which varies in time and space. A linear dynamic analysis of the transient response is carried out by means of the modal superposition technique, in which the static stresses are considered. The results show that in thin shells, the transient displacements could be of the order of the thickness of the shell. It is suggested that these large displacements could play an important role in eroding the buckling capacity of the structural component. The problem of limiting the dynamic displacements is discussed by interaction diagrams for static axial load-dynamic lateral pressure, and by examination of the confluence of shell and wave parameters for which the transient displacements do not exceed a given value. 相似文献