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根据Mindlin理论和Murnaghan模型,首先建立了描述耗散、频散及非线性微结构固体中一维纵波传播的一种简单模型.然后利用有限差分方法,数值模拟了微结构效应对钟型与扭结孤立波演化的影响. 结果表明,随着微结构效应的减弱,钟型孤立波的幅度衰减以及非对称特征变得越来越明显;随着微结构效应的增强,扭结孤立波顶部出现的“帽子”状变化以及由此产生的非对称特征变得越来越明显. 相似文献
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基于RANS方程、VOF方法以及修正的Goring造波方法建立了模拟活塞式推波板运动的二维数值波浪水槽,实现了双孤立波直墙爬高的数值模拟.利用动边界技术模拟造波机推波板的运动,有效地实现了不同波峰间距双孤立波的造波方法.在验证单孤立波直墙爬高的基础上,模拟了不同相对波高、相对波峰间距的等波高双孤立波的直墙爬高过程,给出了波面、速度场及波动能量的变化规律.数值模拟结果表明:对于等波高的双孤立波,当入射波波高较大及两个波峰间距相对较小时,跟随在后孤立波的爬高放大系数小于先导孤立波的爬高放大系数;双孤立波在直墙爬高过程中,波动场的势能时间过程线呈现三峰形态,其中居中的最大势能峰值出现在第二个孤立波与经直墙反射后反向传播的第一个孤立波完全对撞的时刻. 相似文献
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本文讨论了二流体系统界面上内孤立波的分裂,发现上下层流体密度比对分裂成两个内孤立波的条件没有影响,此时只要孤立波从较深的流体运动到较浅的流体就会发生分裂,但分裂成二个以上孤立波的条件受密度比和上游上下层流体厚度比的影响。 相似文献
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分层流体中gKdV型孤立波的迎撞 总被引:1,自引:0,他引:1
本文采用约化摄动法和PLK方法并通过双参数摄动展开,讨论了分层流体中以推广的Korteweg-de vries方程(gKdV方程)描述的孤立波的迎撞问题,求得了二阶近似解。分析结果表明,gKdV型孤立波碰撞后保持原来的形状不变,在碰撞时最大波幅为两个来碰孤立波的最大波幅的线性叠加。 相似文献
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Stable localized nonlinear coherent structures, i.e. solitons, play a key role in the stochastization of the processes occurring in active-dissipative media. In this study, three-dimensional multi-hump solitons are investigated for a model equation which qualitatively describes the wave processes in some physical systems. The existence of 3D multihump solitons is demonstrated numerically and the soliton behavior is studied. The results are generalized to describe multihump solitons in descending viscous-fluid layers [1]. An unusual physical phenomenon observed in experiments [1], namely, stable two-hump coherent structures on the surface of a downflowing viscous-fluid layer, is explained qualitatively. 相似文献
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Numerical simulation of standing solitons and their interaction 总被引:1,自引:0,他引:1
IntroductionThestandingsolitonwasdiscoveredin 1 984byDr.WU[1],aChinesevisitingscholarinU .S .A .fromNanjingUniversity .Hepouredthewaterintoanarrowandlongrectangularchannel,thenputthechannelonaloudspeakerandvibrateditverticallyorhorizontally .Controllingthevibra… 相似文献
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Based on the AfKdV equation of Xu et al.[1], a theory on the velocities of the precursor soliton generation in two-layer flow over topography is presented in the present
paper. Moving velocities of precursor solitons, of the first zero-crossing of the tailing wavetrain and of the flow behind
the topography are found theoretically. It is shown that for a given topography, when its moving velocities are at the resonant
points, we have the following rules: the ratio of the moving velocity of the precursor solitons to that of the first zero-crossing
of the tailing wavetrain equals −4/3. At the same time, the ratio of the width of generating region of the precursor solitons
to that of the depressed water region equals also −4/3. The theoretical results are examined by means of numerical calculation.
The comparison between the theoretical and numerical results are found in good agreement. For different stratified parameters
of two-layer flow, the velocities of the precursor soliton generation are also predicted in terms of the present theoretical
results.
The project supported by the National Natural Science Foundation of China under the Grant No. 49776284 相似文献
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《Wave Motion》2016
Under investigation in this paper are the coupled complex short pulse equations, which describe the propagation of ultra-short optical pulses in cubic nonlinear media. Through the Hirota method, bright–dark one- and two-soliton solutions are obtained. Interactions between two bright or two dark solitons are verified to be elastic through the asymptotic analysis. With different parameter conditions, the oblique interactions, bound states of solitons and parallel solitons are analyzed. 相似文献
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The phenomenon of wave localization in hydroelastic systems leads to the strength concentration of radiation fields. The linear
method considers the process of localization to be the formation of nonpropagation waves (trapped modes phenomenon). The presence
of such waves in the total wave packet points to the existence of mixed natural spectrum of differential operators describing
the behaviour of hydroelastic systems. The problem of liquid and oscillating structure interaction caused by the trapped modes
phenomenon has been solved (membranes, dies). The interaction of the liquid and elastic structures with inclusions can lead
to localized mode formation. In the case of solitary wave motion in nonlinear elastic media, contacting with the liquid, these
solitons can be interpreted as “moving inclusions”. The analytical solution for solitary waves has been found. If the soliton
speed v0 is more than the velocity of sound c0 in the liquid, the solitary waves strongly slow down. If c0 is close to v0,
then a resonance can be observed and solitons move without any resistance. If the soliton speed is less than c0, the solitary
wave slow-down is negligible, compared to the case v0 > c0.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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We are concerned by a special mechanism that can explain the formation of freak waves. We study numerically the long time evolution of a surface gravity wave packet, comparing a fully nonlinear model with Schrödinger-like simplified equations. We observe that the interaction between envelope solitons generates large waves. This is predicted by both models. The fully nonlinear simulations show a qualitative behaviour that differs significantly from the ones preticted by Schrödinger models, however. Indeed, the occurence of freak waves is much more frequent with the fully nonlinear model. This is a consequence of the long-time interaction between envelope solitons, which, in the fully nonlinear model, is totally different from the Schrödinger scenario. The fundamental differences appear for times when the simplified equations cease to be valid. Possible statistical models, based on the latter, should hence under-estimate the probability of freak wave formation. To cite this article: D. Clamond, J. Grue, C. R. Mecanique 330 (2002) 575–580. 相似文献
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本文给出一种Petrov-Galerkin有限元方法,并用以求Kdv方程各种初值问题的数值解,包括孤立波进波解,多个孤立于的相互作用,孤立子与振荡尾波等,所得结果与分析解及其它数值结果作了比较,表明本方法精度高、稳定性好,几乎没有高频伪振荡,计算程序简洁、明瞭,经济实用。 相似文献
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Amplification,reshaping, fission and annihilation of optical solitons in dispersion-decreasing fiber
Chunyu Yang Wenyi Li Weitian Yu Mengli Liu Yujia Zhang Guoli Ma Ming Lei Wenjun Liu 《Nonlinear dynamics》2018,92(2):203-213
Amplification, reshaping, fission and annihilation of optical solitons can be applied in fiber lasers, all-optical switching devices and optical communications. In this paper, for the variable coefficient high-order nonlinear Schrödinger equation, analytic two- and three-soliton solutions are derived by the Hirota bilinear method. Optical solitons propagation in the dispersion-decreasing fibers is investigated theoretically. The influence of corresponding parameters is discussed based on obtained solutions. By choosing properly parameters, optical solitons are amplified and reshaped stably in a long distance. Besides, the number of amplified solitons can be chosen as required. Moreover, a novel phenomenon that three solitons can split into four solitons or merge into two solitons has been proposed. Results may be helpful to realize the amplification, reshaping, fission and annihilation of solitons, and will be valuable to the applications of optical amplifier, all-optical switching and optical self-routing. 相似文献
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《Wave Motion》2017
Bulk strain solitons in solids attract considerable attention in applications due to their very small decay, permanent bell shape and the wave parameter dependence on waveguide elasticity and geometry. One of the reasons of an evident gap between theory and numerical simulation of strain solitons propagation in various waveguides and comparatively rare experimental verification of rigorous results lies in extensive variability of physical constants data available for polymers. We show how a dramatic improvement of experimental setup provides new opportunities in solitary wave observation and its parameters measurements.Digital holography based on high-speed registration cameras allowed us to refine the accuracy of measurements, and precise pulse synchronization provided direct measurements of bulk strain soliton velocity with proper accuracy. It confirms the fact that the soliton parameters depend rather on the waveguide geometry and material, not on an initial pulse, which power provides either a single soliton or a soliton train. 相似文献