共查询到19条相似文献,搜索用时 156 毫秒
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浮在水面上或潜在水下的水平或竖直单板可作为一种新型的防波堤形式.文中应用边界单元方法研究了波浪与这两种板式防波堤结构的相互作用,得到了这两种型式防波堤结构的波浪透射系数和反射系数与板的相对厚度、相对潜深及相对板长之间的相互关系.研究发现:(1)水下平板或立板的透射系数随相对厚度的增大而增大,随着相对潜深的减小而急剧地变小.当板无限接近自由表面时,透射系数会有零值出现.(2)浮在水平面上的平板和立板对中波、短波都有很好的消波效果,且立板消波效果更好.(3)潜在水面下的平板对中波、短波的消波效果比立板好,在整个波浪频率范围内,立板基本没有消波效果. 相似文献
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近自由水面水平板式防波堤消波特性及消波机理研究 总被引:1,自引:0,他引:1
近自由水面刚性水平薄板可作为一种新型的防波堤型式,文章通过应用完全非线性数值波浪水槽技术来探索这种型式防波堤的消波特性和消波机理.研究发现:水平板的浅水效应、透射波浪回流和板后波数分解成一系列高频短波是该种型式防波堤消波的三个重要原因.从工程应用的角度考虑,板的潜深与波高的比值以及板长与波长的比值是决定水平板消波的两个重要参数,合理地调整这两个参数,板式防波堤的透射系数可控制在0.2至0.5之间.由非线性数值模拟结果还可以发现,对于非常接近自由水面的水平板问题而言,会产生不少于3阶的高频短波,这说明用线性理论研究物体近自由水面问题是有局限性的. 相似文献
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为了提升水平板防波堤的消浪性能与透水性能,设计一种迎浪侧半开孔式水平板防波堤。在不同相对板宽、潜深及波高条件下,通过物理模型试验研究不开孔式与迎浪侧半开孔式两种水平板防波堤的透射系数Kt、反射系数Kr及耗能系数Kh,系统对比两种水平板防波堤的消浪性能。结果表明,在试验参数条件下,迎浪侧半开孔式水平板防波堤的透射系数整体上小于不开孔式水平板防波堤,且两种水平板防波堤的透射系数均在相对板宽为0.166或0.212时达到最小值;两种水平板防波堤反射系数的变化趋势相近,迎浪侧半开孔式水平板防波堤的反射系数整体偏小;迎浪侧半开孔式水平板防波堤的耗散系数整体大于不开孔式水平板防波堤,在相对板宽为0.166或0.212时达到最大值。迎浪侧半开孔式水平板防波堤的消浪性能优于不开孔式水平板防波堤。 相似文献
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一种新型透空式防波堤水动力特性试验研究 总被引:2,自引:2,他引:0
采用规则波与不规则波对双层水平板型防波堤进行了一系列的水动力特性试验研究.主要研究了相对板间距s/H,相对潜深w/H两个关键因素对防波堤消浪性能的影响,并探讨了相对板间距s/H,相对潜深w/H对结构双层板总力、上层板总力、下层板总力的影响规律. 相似文献
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文章应用边界单元法,依据波浪绕射和辐射理论研究了一种新型的板式防波堤结构—上弧形板结构。研究中通过与另外三种板式防波堤结构(下弧形板结构,单板结构,双层板结构)的对比,验证了这一新型结构具有更好的消波效果。文中重点分析了这种新型结构的散射波浪力、透射系数和反射系数,并且为了进一步揭示这种结构的消波原理,对该结构周围的流场进了分析。研究发现:(1)上弧形板结构在横荡方向上所受波浪力最小。(2)当潜深波高比为0.05时,该结构的消波效果比其他三种结构增强约50%。(3)通过对上弧形板结构的速度流场分析,发现上弧形板结构上部有明显回流。 相似文献
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高桩码头上部结构波浪力物理模型试验研究 总被引:1,自引:0,他引:1
在不同水位、相同波浪要素组合条件下进行波浪对码头上部结构作用力的模型试验研究,得到上部结构所受最大波浪水平力、最大波浪上托力、最大波浪水平力对应的波浪上托力以及最大波浪上托力对应的波浪水平力,分析最大波浪水平力和最大波浪上托力之间的相位差;并对最大波浪上托力和理论值进行分析比较。试验结果表明:随着水位的增高,作用在码头上部结构的波浪力先增大后减小,在设计高水位时,码头上部结构受到的波浪力最大;最大波浪上托力和最大波浪水平力并不同时出现,存在相位差。 相似文献
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On maximum forces exerted by floating ice on a structure due to constrained thermal expansion of ice
The problem of interaction between a floating ice cover and an engineering structure is considered, in which the ice–structure contact forces are caused by an increase in ice temperature due to solar radiation in situations, when the lateral thermal expansion of ice is constrained. The focus is on the determination of the maximum thermally-induced horizontal force exerted on a structure wall, assuming that the magnitude of this force is bound by the smallest force capable of fracturing the ice cover due to its buckling. The ice cover is modelled as a rectangular plate of uniform thickness, with its four edges being constrained by vertical rigid walls, and it is assumed that ice deforms, and eventually fails, by the mechanism of viscous creep buckling. The plate is subjected to in-plane axial compressive stresses developing in ice to prevent its thermal expansion due to solar heating, and is transversely (vertically) bent by the forces caused by the reaction of underlying water. The floating ice is treated as a material whose elastic and viscous properties depend on temperature and the ice porosity, and therefore they vary with time and the depth of ice. The results of numerical simulations, conducted for a variety of the ice plate horizontal dimensions, thicknesses and daytime temperature-change scenarios, illustrate the evolution of the plate deflection surface prior to its failure, and show the time variation of the maximum forces exerted by ice on a structure wall as functions of the ice thickness and maximum daytime temperature rise at the top surface of ice. 相似文献
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以浙江温州浅滩二期生态堤为例,在波浪港池中开展物理模型试验,探究悬挑框架式海堤在不规则波作用下的受力特性。测量不同入射波条件下海堤直立墙和悬挑的波压强值并分析其随时间变化特性,得到各工况下海堤结构上波压强的分布特征,并探讨结构受力的主要影响因素,对结构所受波浪总力及其影响因素进行冗余分析(RDA)。结果表明:海堤直立墙在波峰作用下,水平方向不同位置受力存在相位差,且潮位以上、以下部分受力过程差异较大;极端工况下海堤直立墙与悬挑连接处所受压强最大;结构整体所受最大竖向总力为5 653.125 kN,约为最大水平总力的70%;有效波高相较于潮位与结构受力的相关性更大。在悬挑框架式海堤设计中,应保证直立墙与悬挑连接处的强度,充分考虑波浪竖向荷载以及最大波高出现情况对整体稳定的影响。 相似文献
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The objective of this paper is to study the nonlinear coupling internal resonance of the heave, roll, and pitch response performance of a spar platform when their frequencies are in the ratio of 2:1:1 under wave and vortex exciting loads. The three degree-of-freedom (DOF) nonlinear coupled equations are established by considering a time-varying wet surface with a first-order wave force in heave and pitch and a vortex-induced force in roll. The first-order steady-state response is solved using the multi-scale method in heave main resonance. The multiple solutions of the motion equations are discussed using the analytic method and a numerical simulation. A sensitivity analysis is conducted to test the influence of the damping and internal detuning parameter. The regions of multiple solutions are found, and the jump phenomenon exists with the changes of the wave excitation. The regions of multiple solutions depend on the values of damping and detuning parameter. 相似文献
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The objective of this paper is to study the nonlinear coupling internal resonance of the heave, roll, and pitch response performance of a spar platform when their frequencies are in the ratio of 2:1:1 under wave and vortex exciting loads.The three degree-of-freedom(DOF) nonlinear coupled equations are established by considering a time-varying wet surface with a first-order wave force in heave and pitch and a vortex-induced force in roll. The first-order steady-state response is solved using the multi-scale method in heave main resonance. The multiple solutions of the motion equations are discussed using the analytic method and a numerical simulation. A sensitivity analysis is conducted to test the influence of the damping and internal detuning parameter. The regions of multiple solutions are found, and the jump phenomenon exists with the changes of the wave excitation. The regions of multiple solutions depend on the values of damping and detuning parameter. 相似文献
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The wave diffraction-radiation problem of a porous geometry of arbitrary shape located in the free surface of a fluid is formulated by a set of integral equations, assuming a linear resistance law at the geometry. The linear forces, the energy relation and the mean horizontal drift force are evaluated for non-porous and porous geometries. A geometry of large porosity has an almost vanishing added mass. The exciting forces are a factor of 5–20 smaller compared to a solid geometry. In the long wave regime, the porous geometry significantly enhances both the damping and the mean drift force, where the latter grows linearly with the wavenumber. The calculated mean drift force on a porous hemisphere and a vertical truncated cylinder, relevant to the construction of fish cages, is compared to available published results. 相似文献