Theoretical method for generating solitary waves using plunger-type wavemakers and its Smoothed Particle Hydrodynamics validation
Theoretical method for generating solitary waves using plunger-type wavemakers and its Smoothed Particle Hydrodynamics validation
复制标题
柱塞式造波器产生孤立波的理论方法及其平滑粒子流体动力学验证
DOI：
10.1016/j.apor.2020.102414
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发表时间：
2021-01-22
影响因子：
4.3
通讯作者：
Liu, Bijin
中科院分区：
文献类型：
--
作者：
He, Ming;Khayyer, Abbas;Liu, Bijin
虽然使用活塞式造波机产生孤立波已经很常见，但该方法不能应用于所有的波浪水槽，因为它们中的许多已经或将配备柱塞式造波机。如何利用柱塞产生和活塞一样好的孤立波是一个尚未解决但有实际意义的问题。在此，提出了一种理论方法。推导了任意形状柱塞精确下降的新公式，并给出了产生波高的约束条件。以楔形、箱形和圆柱形柱塞为例，详细说明了一般的兴波理论和约束条件。在此基础上，采用光滑粒子流体动力学（SPH）模型对孤立波的产生进行了模拟，并通过再现已有的实验结果验证了SPH模型的可靠性。通过将SPH结果与解析解进行比较，检查了SPH模拟的波浪剖面、速度场和压力场。此外，还对柱塞式和活塞式以及瑞利法和Boussinesq法产生的孤立波进行了比较。结果表明，只要柱塞不具有尖角或与波廓不相容的表面，柱塞式造波机所产生的孤立波可以与活塞式造波机所产生的孤立波一样精确。因此，预计所提出的理论将扩展现有的柱塞式造波机的功能，并有利于柱塞设计在未来。
Although solitary wave generation using a piston-type wavemaker has been common, the method cannot be applied to all wave tanks because many of them have been or will be equipped with plunger-type wavemakers. How to use a plunger to generate solitary waves as good as those generated by a piston is an unsolved but practically significant problem. Herein, a theoretical method is proposed. New formulae for the precise descent of an arbitrary-geometry plunger are derived and constraints on the produced wave height are given. Taking wedge-shaped, box-shaped, and cylinder-shaped plungers as examples, the generic wave-making theory and constraints are then specified. On their bases a Smoothed Particle Hydrodynamics (SPH) model is applied to simulate the solitary wave generation, and its reliability is validated in advance by reproducing available experiments. The SPH-simulated wave profiles, velocity fields, and pressure fields are examined by comparing SPH results with analytical solutions. In addition, plunger-type and piston-type as well as Rayleigh-based and Boussinesq-based solitary wave generation are compared. The results show that the solitary wave generated by a plunger-type wavemaker can be as accurate as the one generated by a piston-type wavemaker, provided that the plunger does not have a sharp corner or an incompatible surface with the wave profile. It is therefore anticipated that the proposed theory will extend the functionalities of existing plunger-type wavemakers and benefit plunger design in the future.