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不规则波Boussinesq型方程的造波,消波和反射 总被引：5，自引：1，他引：4
对前人提出的造波、消波和反射边方法分析表明,其方法是极浅水波近似,不适用于任意水深的水域,本文就任意水深变化Ｂｏｕｓｓｉｎｅｓｑ型方程,提出了不规则波新的造波原理、方法和消波边界及部分反射边界波动方程,试验表明,本文提出的造波、消波和反射方程有效而可靠的。 相似文献
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提出了一种新型内波造波方法——箱内垂荡板式造波。应用 FLUENT 软件的有限体积法,采用 k-ε两方程湍流模型封闭 RANS 方程作为求解控制方程,建立二维数值内波水槽。通过模仿物理造波机运动的数值模拟结果比较表明：箱内垂荡板式造波机生成的内波与理论解十分吻合,与双板联动式造波和平板拍击式造波相比,控制简单,对自由水面的扰动小,对水槽水深的变化和分层界面位置的改变适应性好,不会造成分层水体的掺混。 相似文献
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基于FLUENT的海洋内孤立波数值水槽模拟 总被引：3，自引：0，他引：3
基于FLUENT商业软件及其二次开发功能,在标准κ-ε湍流模型下,采用VOF方法追踪两层流体内界面,通过给定入口速度和水位的设置造波边界法,建立了可有效模拟弱非线性内孤立渡的分层流数值水槽,并与仿物理的双板造波方法进行了比较.采用设置边界法所造的波形与理论值符合较好,这为数值分析内孤立渡与海洋结构物相互作用问题提供了一条更加有效的途径. 相似文献
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非线性波消波及波场分布研究 总被引：1，自引：1，他引：0
本文基于雷诺平均N-S方程,并结合RNG k-e方程建立了粘性数值波浪水槽,对不同波陡、不同相对水深、不同相对波高的非线性规则波的阻尼消波问题和波场分布进行研究。文中提出了两种描述消波区内部阻尼变化的阻尼函数,分别适用于小波陡情形和高波陡情形。研究结果表明,小波陡组消波区可设为一个波长,阻尼系数取10~4～10~5即可满足消波要求,计算结果与实验结果及造波理论吻合良好;高波陡组消波区可设为两个波长,阻尼系数取10~4～10~5亦可满足消波要求,计算结果与实验结果吻合良好。此外,当波陡较小时,波场内反射情况的小幅改变即可对整个波场造成影响,特别是当水深较浅时这种影响极为明显,需谨慎考虑。当波陡较大时,水波能量较高,整个波场沿水波传播方向可观测到明显的衰减现象,在具体试验中需进行考虑。 相似文献
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为研究内孤立波质量源数值造波方法,本文采用两个点源形式的质量源,分别放置于两层流体的上下层中作为内孤立波激发源。推导源项表达式,从不可压缩流体的Navier-Stokes方程出发,结合内孤立波Kd V、e Kd V理论,基于商业软件FLUENT发展了一种内孤立波质量源数值造波方法。通过数值模拟,分析了质量源造波过程中内孤立波的生成过程,并将数值模拟结果同理论及实验作对比。结果表明:基于此方法生成的内孤立波波形、波高及波致水平速度与理论及实验吻合度较好,该方法是可行的,并且耗时短、效率高。 相似文献
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概述了国内外学者对freak波的认识，并从各种观测资料分析总结了freak波的特征。引入完全非线性控制方程Schroedinger方程的1＋1模式，对freak波进行模拟，为在实验室造波或计算研究提供一种方法。 相似文献
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非静压波浪模型是一种近年来得到迅速发展且有望在工程计算中获得广泛应用的波浪模型。为了在非静压波浪模型中实现无反射造波,在连续性方程中添加了质量源项进行域内源造波,并采用阻尼消波方法进行数值消波。数值算例结果表明,所建立的无反射造波方法可以较好地避免非静压波浪数学模型中的二次反射,实现长时间稳定波浪模拟。 相似文献
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多向不规则波有效试验区的扩展法 总被引：3，自引：2，他引：3
实验室中一般采用分段式造波机来产生斜向或多向波，但其中存在几个问题，最主要的是有效试验区较小。扩大有效试验区的常用方法是采用边墙反射法。本文首先叙述了应用边墙反射产生斜向波和多向波的方法，通过物理模型试验对该方法进行了验证，试验结果表明采用边墙反射的确可以扩大有效试验区的范围。 相似文献
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It is difficult to compute far-field waves in a relative large area by using one wave generation model when a large calculation domain is needed because of large dimensions of the waterway and long distance of the required computing points. Variation of waterway bathymetry and nonlinearity in the far field cannot be included in a ship fixed process either. A coupled method combining a wave generation model and wave propagation model is then used in this paper to simulate the wash waves generated by the passing ship. A NURBS-based higher order panel method is adopted as the stationary wave generation model; a wave spectrum method and Boussinesq-type equation wave model are used as the wave propagation model for the constant water depth condition and variable water depth condition, respectively. The waves calculated by the NURBS-based higher order panel method in the near field are used as the input for the wave spectrum method and the Boussinesq-type equation wave model to obtain the far-field waves. With this approach it is possible to simulate the ship wash waves including the effects of water depth and waterway bathymetry. Parts of the calculated results are validated experimentally, and the agreement is demonstrated. The effects of ship wash waves on the moored ship are discussed by using a diffraction theory method. The results indicate that the prediction of the ship induced waves by coupling models is feasible. 相似文献
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A semi-analytical nonlinear wavemaker model is derived to predict the generation and propagation of transient nonlinear waves in a wave flume. The solution is very efficient and is achieved by applying eigenfunction expansions and FFT. The model is applied to study the effect of the wavemaker and its motion on the generation and propagation of nonlinear waves. The results indicate that the linear wavemaker theory may be applied to predict only the generation of waves of low steepness for which the nonlinear terms in the kinematic wavemaker boundary condition and free-surface boundary conditions are of secondary importance. For waves of moderate steepness and steep waves these nonlinear terms have substantial effects on wave profile and wave spectrum just after the wavemaker. A wave spectrum corresponding to a sinusoidally moving wavemaker possesses a multi-peak form with substantial nonlinear components, which disturbs or may even exclude physical modeling in wave flumes. The analysis shows that the widely recognized weakly nonlinear wavemaker theory may only be applied to describe the generation and propagation of waves of low steepness. This is subject to further restrictions in shallow and deep waters because the kinematic wavemaker boundary condition as well as the nonlinear interaction of wave components and the evolution of wave energy spectrum is not properly described by weakly nonlinear wavemaker theory. Laboratory experiments were conducted in a wave flume to verify the nonlinear wavemaker model. The comparisons show a reasonable agreement between predicted and measured free-surface elevation and the corresponding amplitudes of Fourier series. A reasonable agreement between theoretical results and experimental data is observed even for fairly steep waves. 相似文献
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We develop techniques of numerical wave generation in the time-dependent extended mild-slope equations of Suh et al. [1997. Time-dependent equations for wave propagation on rapidly varying topography. Coastal Engineering 32, 91–117] and Lee et al. [2003. Extended mild-slope equation for random waves. Coastal Engineering 48, 277–287] for random waves using a source function method. Numerical results for both regular and irregular waves in one and two horizontal dimensions show that the wave heights and the frequency spectra are properly reproduced. The waves that pass through the wave generation region do not cause any numerical disturbances, showing usefulness of the source function method in avoiding re-reflection problems at the offshore boundary. 相似文献
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Efficient Simulation of Freak Waves in Random Oceanic Sea States 总被引：1，自引：0，他引：1
Numerical simulations of freak wave generation are studied in random oceanic sea states described by JONSWAP spectrum.The evolution of initial random wave trains is numerically carried out within the framework of the modified fourorder nonlinear Schruedinger equation (mNLSE),and some involved influence factors are also discussed.Results show that if the sideband instability is satisfied,a random wave train may evolve into a freak wave train,and simultaneously the setting of the Phillips parameter and enhancement coefficient of JONSWAP spectrum and initial random phases is very important for the formation of freak waves.The way to increase the generation efficiency of freak waves thsough changing the involved parameters is also presented. 相似文献
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The problem of wave propagation in a fully nonlinear numerical wave tank is studied using desingularized boundary integral equation method coupled with mixed Eulerian–Lagrangian formulation. The present method is employed to solve the potential flow boundary value problem at each time step. The fourth-order predictor–corrector Adams–Bashforth–Moulton scheme is used for the time-stepping integration of the free surface boundary conditions. A damping layer near the end-wall of wave tank is added to absorb the outgoing waves with as little wave reflection back into the wave tank as possible. The saw-tooth instability is overcome via a five-point Chebyshev smoothing scheme. The model is applied to several wave propagations including solitary, irregular and random incident waves. 相似文献
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为了研究斜向入射波浪,基于三维不可压缩两相流模型,开发了一套圆形数值波浪水池数值模型。在圆形波浪水池中,通过源项造波法成功生成了任意入射方向的波浪,并且利用人工摩擦项模拟阻尼区以数值耗散反射波浪。模型基于嵌入式多块网格体系,采用FVM法(finite volume method)离散Navier-Stokes方程,VOF法(volume of fluid)追踪自由水面。试验结果表明,斜向入射波浪的模拟结果与理论值基本一致,圆形波浪水池在模拟斜向入射波浪时,有效区域的面积较传统波浪水池显著增大,而且有效区域受波浪入射角度的影响也较小。同时,通过叠加多列斜向入射波浪,模拟出了多向交叉波列,并通过与理论结果对比,发现其具有较高的精度。 相似文献
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This paper presents the numerical solution of a new nonlinear mild-slope equation governing waves with different frequency components propagating in a region of varying water depth. There are two new nonlinear equations. The linear part of the equations is the mild-slope equation, and one of the models has the same non-linearity as the Boussinesq equations. The new equations are directly applicable to the problems of nonlinear wave-wave interactions over variable depth. The equations are first simplified with the parabolic approximation, and then solved numerically with a finite difference method. The Crank-Nicolson method is used to discretize the models. The numerical models are applied to a set of published experimental cases, which are nonlinear combined refraction-diffraction with generation of higher harmonic waves. Comparison of the results shows that the present models generally predict the measurements better than other nonlinear numerical models which have been applied to the data set. 相似文献
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A numerical solution is developed to investigate the generation and propagation of small-amplitude water waves in a semi-infinite rectangular wave basin. The three-dimensional wave field is produced by the prescribed “snake-like” motion of an array of segmented wave generators located along the wall at one end of the tank. The solution technique is based on the boundary element approach and uses an appropriate three-dimensional Green function which explicitly satisfies the tank-wall boundary conditions. The Green function and its derivatives which appear in the integral equation formulation can be shown to be slowly convergent when the source and field points are in close proximity. Therefore, when computing the velocity potentials on the wave generators, the source points are chosen outside the fluid domain, thereby ensuring the rapid convergence of these functions and rendering the integral equations non-singular. Numerical results are shown which illustrate the influence of the various wavemaker and basin parameters on the generated wave field. Finally, the complete wave field produced by the diffraction of oblique waves by a vertical circular cylinder in a basin is presented. 相似文献