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Smrutiranjan Mohapatra 《船舶与海洋工程学报》2014,(3)
Obliquely incident water wave scattering by an uneven channel-bed in the form of a small bottom undulation in a two-layer fluid is investigated within the frame work of three-dimensional linear water wave theory. The upper fluid is assumed to be bounded above by a rigid lid, while the lower one is bounded below by a bottom surface having a small deformation and the channel is unbounded in the horizontal directions. Assuming irrotational motion, perturbation technique is employed to calculate the first-order corrections to the velocity potentials in the two fluids by using Fourier transform approximately, and also to calculate the reflection and transmission coefficients in terms of integrals involving the shape function representing the bottom deformation. Consideration of a patch of sinusoidal ripples shows that the reflection coefficient is an oscillatory function of the ratio of twice the component of the wave number along x-axis and the ripple wave number. When this ratio approaches one, the theory predicts a resonant interaction between the bed and interface, and the reflection coefficient becomes a multiple of the number of ripples. High reflection of incident wave energy occurs if this number is large. 相似文献
203.
Smrutiranjan Mohapatra 《船舶与海洋工程学报》2014,(2)
Scattering of surface waves by the edge of a small undulation on a porous bed in an ocean of finite depth, where the free surface has an ice-cover being modelled as an elastic plate of very small thickness, is investigated within the framework of linearized water wave theory. The effect of surface tension at the surface below the ice-cover is neglected. There exists only one wave number propagating at just below the ice-cover. A perturbation analysis is employed to solve the boundary value problem governed by Laplace's equation by a method based on Green's integral theorem with the introduction of appropriate Green's function and thereby evaluating the reflection and transmission coefficients approximately up to first order. A patch of sinusoidal ripples is considered as an example and the related coefficients are determined. 相似文献
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透水框架作为一种减速促淤的整治建筑物,近年来在航道整治工程逐步得到推广,在守护工程中应用最为广泛.长江航道规划设计研究院研发了一种新型透水框架——扭双工字型透水框架,并在南京以下12.5 m深水航道建设一期工程通州沙潜堤护底中进行了试验性应用.确定合理的透水框架护底检验标准,是保证防护效果的重要基础,而目前的航道整治工程质量检验标准,并未对此作出明确规定.通过水槽试验提出透水框架护底的检验标准,利用测扫声呐图像分析提出相应的检验方法,并进行了室内光学图像试验验证,符合较好. 相似文献
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船艏底部作为整船中的重要受力区域,船舶航行时,其与波浪会发生相对碰撞,即产生砰击现象,从而对船体的结构安全造成隐患。本文以某型半潜运输船为例,结合中国船级社(CCS)规范,根据Ochi-Mottor理论进行砰击压力极值计算,并采用有限元方法对该型船舶艏部区域的结构强度进行分析。 相似文献