共查询到18条相似文献,搜索用时 203 毫秒
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造波板运动造波的实时模拟 总被引:3,自引:0,他引:3
基于势流理论和时域高阶边界元方法,建立了完全非线性数值波浪水槽模型,通过实时模拟造波板运动来产生波浪.采用混合欧拉-拉格朗日方法追踪流体瞬时水面,运用四阶Runga-Kutta方法更新下一时间步的波面和速度势,同时应用镜像格林函数消除了水槽两个侧面和底面上的积分,在水槽末端布置人工阻尼层消除反射波浪,通过加速势的方法准确计算速度势的时间导数.利用所建模型分别对规则波和不规则波进行了模拟研究,得到了稳定的波形,与试验结果、理论结果和已发表结果均吻合良好,同时计算了造波板做单一频率运动产生的非线性波浪力. 相似文献
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无反射造波数值波浪水槽 总被引:21,自引:11,他引:21
王永学 《水动力学研究与进展(A辑)》1994,(2):205-214
本文应用VOF方法建立了二维数值波浪水槽模型。基于线性造波机理论在水槽左端设置了可吸收式造波机数值边界条件。即造波板的运动除了产生行进波外,同时还产生一个抵消反射波的局部波动。水槽右端除了通常的可滑移与无滑移直墙边界条件外,依据线性辐射条件建立了开边界条件。通过水槽右端为直墙时的全反射情形,比较了可吸收造波机与普通造波机的速度变化与波面变化。文中在H0/d=0.1 ̄0.3,d/L=0.124 ̄0. 相似文献
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机械式造波机的机构设计及其运动性能分析 总被引:1,自引:1,他引:0
为满足实验室进行水槽试验时对波浪的要求,在机械式造波机机构简图的基础上进行了严格的理论分析,并提出了机构设计所遵循的一般原则:①涡轮电机输出转盘的半径r0应尽可能小;②系数比ι2/ι3(涡轮电机输出转盘中心至造波机摇板转动点的距离ι2与摇板转动力臂ι3之比)尽可能大。通过数值计算研究了造波机摇板的运动特性,表明造波机摇板的运动规律是简谐的,造出的波浪也符合简谐规律。同时指出,造波机摇板平衡位置的偏移角与系数比相关,系数比越大,则偏移角越小。 相似文献
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VOF方法模拟波浪槽中二维非线性波 总被引:10,自引:0,他引:10
造波板运动生成非线性波问题是研究物体与波浪非线性相互作用的典型例子。本文研究了用VOF方法模拟波浪水槽生成非线性波(孤立波和椭圆余弦波)的问题,为实现造波板在计算中可以做穿越网格的大幅值运动,本文采用在压力迭代中调整造波板邻近单元中压力来满足造波板上流体运动条件。对开路边界条件和自由表面与物面交点处边界条件也提出了处理方法,计算结果与实验结果和解析结果进行了对比。 相似文献
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基于VOF方法的数值波浪水槽以及造波、消波方法研究 总被引:12,自引:4,他引:8
该文基于不可压缩黏性流体的N-S方程和VOF方法,利用CFD商业软件FLUENT及其二次开发功能,发展和提出了动边界造波、多孔介质消波等多种数值方法,建立了可有效模拟弱非线性波的数值波浪水槽.同时对现有的几种造波-消波方法进行了详细的分析,综合比较了不同方法的优劣性,指出了本文提出的多孔介质消波法可更有效的吸收波能,给出了造波-消波的最优配置. 相似文献
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为了研究波群作用下的船舶参数激励横摇特性,该文引入了高阶无旋层析水波理论(HLIGN)开展波群的数值模拟研究。结合C11集装箱船顶浪不规则波参数横摇模型试验的测试数据,选取目标波群样本,通过二阶非线性造波理论获得了波群造波水池试验结果。利用全非线性波浪模型对波群进行数值模拟,给出了波群模拟时的造波边界设置和计算参数设置方法,并通过与物理造波结果对比发现,HIGN波浪模型对波群模拟有较高的精度,可很好地模拟波群的非线性传播特性。 相似文献
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为了使数值波浪水槽模型能够精确简便地代替物理模型,并为港口海洋工程及内河工程提供重要的数据支持,基于不可压缩黏性流体的N-S方程和VOF方法,运用软件FLUENT建立数值水槽。通过对软件的二次开发,进行推波板造波方法的波浪数值模拟。将物理模型实验中的Sch?ffer二阶造波理论运用于波浪数值模拟,实现基于二阶推波板造波法的双频波数值模拟。在此造波基础上,开创性地模拟出变化地形下波浪的相互作用,体现出其非线性作用。研究结果显示:(1)将各工况得出数据分别与理论值和实验值进行对比验证,表明所用方法有较好的精确性;(2)通过双色波相互作用后的频域分析得出其适用范围为0.1h/L0.5。推波板造波法模拟的数值波浪有着较好的非线性和精确性,可以在一定条件下代替物理实验。 相似文献
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朱关年 《水利水电科技进展》1981,(4)
<正> 波浪发生机是海洋工程、港口工程和船舶工程领域中进行试验研究的重要设备。为了模拟自然界的波浪要素,国内很多单位都在摸索和试制不规则生波机。本文将介绍法国水工技术工厂制造的可改变波向的不规则生波机和水槽中使用的不规则生波机。生波机的工作原理:波浪由绕轴摆动的推扳产生,推扳由一小惯量的直流变速马达驱动,通过电子设备对马达的控制,使波浪的振幅和周期能很精确地得到调整,以模拟连续变化的波浪模式,不需要停机就能在运转中改变波浪的要素。 相似文献
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本文介绍了国外引进的电液伺服摇板式造波机控制系统技术改造的方法,其中包括更换控制系统计算机以及改进数据传输链路,并将单台计算机控制方式改造成双台计算机主从式控制等。利用VB语言对造波机系统控制软件重新设计开发,实现了WINDOWS环境下的造波控制,恢复了该造波机对二雏非规则波的模拟功能,并把规则波的模拟范围扩展到二阶精度,提高了造波品质。 相似文献
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浅海人工岛波浪爬高的数值计算和实验验证 总被引:1,自引:0,他引:1
本文基于孤立波理论研究了浅海波浪对人工岛的非线性绕射,提出了采用有限差分法和有限远开边界的幅射条件计算人工岛上波浪爬高的数值模型,得到的数值计算结果与整体模型试验的实测结果进行了比较,二者吻合较好,为人工岛工程设计提供了可靠的高度参数。 相似文献
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In sustainable water resources management, it is essential to rank inter-basin water transfer projects. This task is difficult due to many different conflict criteria, complex relations among criteria and various judgments of decision makers. In this paper, an integrated multiple attribute group decision making method consists of ANP (Analytical Network Process), fuzzy TOPSIS and fuzzy max-min set methods is proposed for evaluating water transfer projects. A set of over 60 criteria in social, environmental and economic sectors are used for ranking four water transfer projects in Karun River based on three decision maker judgments. A key novelty of the proposed methodology is its ability to model both complex relations among different criteria in water management and the influence of decision maker judgments’ weights on the final ranking in group decision making problem. The procedure starts by obtaining the priority of water transfer projects and the weight of each decision maker judgments by employing ANP and fuzzy TOPSIS, respectively. These weights are used as inputs in the fuzzy max-min set method. Then the effects of decision maker weights on the final ranking are determined in fuzzy environment. Finally, the sensitivity analysis of decision makers’ weights has been conducted. The results show that the proposed method is an effective tool for group decision making problems by considering different criteria and decision makers’ weights. 相似文献
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ZHOU Bin-zhen NING De-zhi TENG Bin CHEN Li-fen 《水动力学研究与进展(B辑)》2010,22(3):402-409
Based on the eigenfunction expansion technique, the wave generation by a piston wave maker in a wave flume with a partially reflecting end-wall is studied. The corresponding velocity potential and wave elevation in the flume are obtained. The present analytical solution is verified by the numerical results obtained from a time-domain higher-order boundary element method in a closed flume. Numerical experiments are further carried out to study the difference between the partial/full reflection boundary and the transmission boundary and the effects of the reflection coefficient and the motion period of the wave maker on the wave height. Meanwhile, the natural frequency of the wave flume can be obtained from the analytical expression. The resonance occurs when the motion frequency is equal to the natural frequency. Even the partial reflection of the end-wall in the wave flume experiments has a great influence on the wave height, therefore, inaccurate measurements would be resulted in long-time simulations, especially when the wave frequency approaches the wave flume natural frequency. The present study can serve as a guidance for the physical experiment in wave flumes. 相似文献
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《水科学与水工程》2016,(1)
This paper describes an investigation of the generation of desired sea states in a numerical wave model. Bimodal sea states containing energetic swell components can be coastal hazards along coastlines exposed to large oceanic fetches. Investigating the effects of long-period bimodal seas requires large computational domains and increased running time to ensure the development of the desired sea state. Long computational runs can cause mass stability issues due to the Stokes drift and wave reflection, which in turn affect results through the variation of the water level. A numerical wave flume, NEWRANS, was used to investigate two wave generation methods: the wave paddle method, allowing for a smaller domain; and the internal mass source function method, providing an open boundary allowing reflected waves to leave the domain.The two wave generation methods were validated against experimental data by comparing the wave generation accuracy and the variance of mass in the model during simulations. Results show that the wave paddle method not only accurately generates the desired sea state but also provides a more stable simulation, in which mass fluctuation has less of an effect on the water depth during the long-duration simulations. As a result, it is suggested that the wave paddle method with active wave absorption is preferable to the internal wave maker option when investigating intermediate-depth long-period bimodal seas for long-duration simulations. 相似文献
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A scale modeled discus data buoy was tested for its motion characteristics under the action of wave groups of different frequencies in a wave tank. The wave groups were theoretically simulated based on the methodology of Xu et al., (1993, Statistical simulation of wave groups, Applied Ocean Research, 15, 217–226) and then converted to paddle displacement signals to drive the wave maker. The motion responses of the buoy model were measured using potentiometers as well as with a non-contact motion tracking camera system. The details of the model, instrumentation, testing conditions and the analysis are presented. The displacement and wave elevation time histories were analysed through statistical, envelope, wavelet transform and phase-time approaches to detect the wave groupiness. The effect of groupiness parameters on the surge, heave and pitch motions of the buoy are detailed in this paper. 相似文献