直立摇板简谐摇荡造二维波时所受水动力矩的频域二阶解和时域线性解

本文给出直立摇板简谐摇荡造二维波时所受水动力矩的频域二阶解和时域线性解的解析表达式,可供估算摇板式造波机设计功率时使用,也可为摇板所受水动力矩时域非线性数值计算提供比较的依据。     

DuaISPHysics：A numerical tool to simulate real breakwaters

The open-source code DualSPHysics is used in this work to compute the wave run-up in an existing dike in the Chinese coast using realistic dimensions, bathymetry and wave conditions. The GPU computing power of the DualSPHysics allows simulating real-engineering problems that involve complex geometries with a high resolution in a reasonable computational time. The code is first validated by comparing the numerical free-surface elevation, the wave orbital velocities and the time series of the run-up with physical data in a wave flume. Those experiments include a smooth dike and an armored dike with two layers of cubic blocks. After validation,the code is applied to a real case to obtain the wave run-up under different incident wave conditions. In order to simulate the real open sea, the spurious reflections from the wavemaker are removed by using an active wave absorption technique.     

基于Windows的摇板式造波机波浪模拟技术研究

造波机是船模耐波性水池主要的实验设备,其波浪模拟性能对船模耐波性试验具有很大影响．以早期从国外引进的水池摇板式造波机为研究对象,分析了该造波机的系统构成,介绍了利用摇板式造波机在船模试验水池中进行人工波浪模拟的原理及控制方法．给出了造波控制系统的传递函数及波浪目标谱的修正方法,并将原DOS系统下的系统控制应用软件进行升级改造,开发出适用于WINDOWS操作系统下波浪模拟控制程序．提出了利用VB软件编制实时控制应用程序时确定控制信号离散周期与生成软件定时器的方法,使造波机在WINDOWS环境下也能在水池中进行规则波与二维非规则波的模拟,恢复了该造波机对二维非规则波的模拟功能．通过试验测试及实际工程项目的验证,取得了满意的效果．这一技术可为造波机控制系统设计与改造的研究人员提供参考．     

深水池造波系统数值造波仿真研究

造波系统作为哈尔滨工程大学新建多功能深水综合试验水池的重要组成部分,对其进行相关的数值仿真研究具有现实意义.基于摇板式造波机理论和阻尼层消波思想,使用VOF方法,结合RNGk-ε模型,通过求解Navier-Stokes方程,建立了与该深水综合试验水池相应的二维数值波浪水池,对深水池造波机生成二维规则波及不规则波时的情况进行了数值造波仿真,给出了该数值波浪水池的波浪衰减规律,数值计算的结果表明,数值波浪水池内可以长时间地产生稳定的规则波和指定谱型的不规则波,为深水池造波机控制系统调试及水池波形的测量提供了依据.     

Trapping and Near-Trapping by Arrays of Cylinders in Waves

In this paper, some recent developments and new results concerning the trapping of waves by arrays of vertical circular cylinders is presented. In particular, the cases are examined when there is a circular arrangement of cylinders and both finite and infinite periodic linear arrays of identical cylinders. Only for the infinite array is there pure trapping of waves – known as Rayleigh–Bloch or edge waves – which, for particular dominant wavenumbers, reduce to the well-known trapped-mode solutions for a cylinder between two parallel walls having either Neumann or Dirichlet conditions upon them. This latter case is considered separately and some new results are presented. In the circular array and finite linear array the concept of near-trapping is introduced where large resonant motions are found to occur at certain frequencies of the incident wave field. In the case of the finite linear array, these near-trapping frequencies are related to the Rayleigh–Bloch trapped-wave frequencies for the infinite array. Finally, the case when there are two or more lines of cylinders in the linear array is examined.     

电液伺服冲箱式造波机控制系统研究

介绍了电液伺服冲箱式造波机控制系统的组成，原理以及软件实现，分析了Windows系统中普通定时器和多媒体定时器的工作机理，研究了多媒体时钟的定制和使用方法，该定时器非常适宜于一般实时控制系统。     

摇板式造波机所造二维波的完全非线性解

本文采用边界积分方程的时间步进法对摇板式造波机所造二维波的波形及遥板所受水动力矩求完全非线性解。对于自由面和摇板交点处自由面条件和物面条件的相容性作了专门的考虑。在弱非线性情况下，规则波时域非线性的计算结果与频域二阶解及时域线性解作了比较，验证本文的数值方法是可行的。     

FULLY NONLINEAR CALCULATION OF 2－D WATER WAVE GENERATED BY ROCKER FLAP WAVEMAKER

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Corner problems and global accuracy in the boundary element solution of nonlinear wave flows

The numerical model for nonlinear wave propagation in the physical space, developed by Grilli, et al.^12,13, uses a higher-order BEM for solving Laplace's equation, and a higher-order Taylor expansion for integrating in time the two nonlinear free surface boundary conditions. The corners of the fluid domain were modelled by double-nodes with imposition of potential continuity. Nonlinear wave generation, propagation and runup on slopes were successfully studied with this model. In some applications, however, the solution was found to be somewhat inaccurate in the corners and this sometimes led to wave instability after propagation in time.

In this paper, global and local accuracy of the model are improved by using a more stable free surface representation based on quasi-spline elements and an improved corner solution combining the enforcement of compatibility relationships in the double-nodes with an adaptive integration which provides almost arbitrary accuracy in the BEM numerical integrations. These improvements of the model are systematically checked on simple examples with analytical solutions. Effects of accuracy of the numerical integrations, convergence with refined discretization, domain aspect ratio in relation with horizontal and vertical grid steps, are separately assessed. Global accuracy of the computations with the new corner solution is studied by solving nonlinear water wave flows in a two-dimensional numerical wavetank. The optimum relationship between space and time discretization in the model is derived from these computations and expressed as an optimum Courant number of 0.5. Applications with both exact constant shape waves (solitary waves) and overturning waves generated by a piston wavemaker are presented in detail.