scholarly journals The general coupled Hirota equations: modulational instability and higher-order vector rogue wave and multi-dark soliton structures

2019 ◽  
Vol 475 (2222) ◽  
pp. 20180625 ◽  
Author(s):  
Guoqiang Zhang ◽  
Zhenya Yan ◽  
Li Wang
Keyword(s):  
Nonlinear Wave ◽  
Rogue Wave ◽  
Modulational Instability ◽  
Distribution Patterns ◽  
Rogue Waves ◽  
Dark Soliton ◽  
Scalar Model ◽  
Optical Fields ◽  
Dark Solitons ◽  
Hirota Equations

The general coupled Hirota equations are investigated, which describe the wave propagations of two ultrashort optical fields in a fibre. Firstly, we study the modulational instability for the focusing, defocusing and mixed cases. Secondly, we present a unified formula of high-order rational rogue waves (RWs) for the focusing, defocusing and mixed cases, and find that the distribution patterns for novel vector rational RWs of focusing case are more abundant than ones in the scalar model. Thirdly, the N th-order vector semirational RWs can demonstrate the coexistence of N th-order vector rational RWs and N breathers. Fourthly, we derive the multi-dark-dark solitons for the defocsuing and mixed cases. Finally, we derive a formula for the coexistence of dark solitons and RWs. These results further enrich and deepen the understanding of localized wave excitations and applications in vector nonlinear wave systems.

Rogue wave occurrence and dynamics by direct simulations of nonlinear wave-field evolution

2013 ◽  
Vol 720 ◽  
pp. 357-392 ◽  
Author(s):  
Wenting Xiao ◽  
Yuming Liu ◽  
Guangyu Wu ◽  
Dick K. P. Yue
Keyword(s):  
Wave Field ◽  
Linear Theory ◽  
Nonlinear Wave ◽  
Rogue Wave ◽  
Modulational Instability ◽  
Rogue Waves ◽  
Single Wave ◽  
Gaussian Statistics ◽  
Non Gaussian ◽  
Nonlinear Wave Field

AbstractWe study the occurrence and dynamics of rogue waves in three-dimensional deep water using phase-resolved numerical simulations based on a high-order spectral (HOS) method. We obtain a large ensemble of nonlinear wave-field simulations ($M= 3$ in HOS method), initialized by spectral parameters over a broad range, from which nonlinear wave statistics and rogue wave occurrence are investigated. The HOS results are compared to those from the broad-band modified nonlinear Schrödinger (BMNLS) equations. Our results show that for (initially) narrow-band and narrow directional spreading wave fields, modulational instability develops, resulting in non-Gaussian statistics and a probability of rogue wave occurrence that is an order of magnitude higher than linear theory prediction. For longer times, the evolution becomes quasi-stationary with non-Gaussian statistics, a result not predicted by the BMNLS equations (without consideration of dissipation). When waves spread broadly in frequency and direction, the modulational instability effect is reduced, and the statistics and rogue wave probability are qualitatively similar to those from linear theory. To account for the effects of directional spreading on modulational instability, we propose a new modified Benjamin–Feir index for effectively predicting rogue wave occurrence in directional seas. For short-crested seas, the probability of rogue waves based on number frequency is imprecise and problematic. We introduce an area-based probability, which is well defined and convergent for all directional spreading. Based on a large catalogue of simulated rogue wave events, we analyse their geometry using proper orthogonal decomposition (POD). We find that rogue wave profiles containing a single wave can generally be described by a small number of POD modes.

scholarly journals Rogue Waves With Rational Profiles in Unstable Condensate and Its Solitonic Model

2021 ◽  
Vol 9 ◽  
Author(s):  
D. S. Agafontsev ◽  
A. A. Gelash
Keyword(s):  
Plane Wave ◽  
Stationary State ◽  
Rogue Wave ◽  
Modulational Instability ◽  
Soliton Solutions ◽  
Rogue Waves ◽  
Bound State ◽  
Wave Formation ◽  
Soliton Interaction ◽  
Long Time

In this brief report we study numerically the spontaneous emergence of rogue waves in 1) modulationally unstable plane wave at its long-time statistically stationary state and 2) bound-state multi-soliton solutions representing the solitonic model of this state. Focusing our analysis on the cohort of the largest rogue waves, we find their practically identical dynamical and statistical properties for both systems, that strongly suggests that the main mechanism of rogue wave formation for the modulational instability case is multi-soliton interaction. Additionally, we demonstrate that most of the largest rogue waves are very well approximated–simultaneously in space and in time–by the amplitude-scaled rational breather solution of the second order.

Hunting for Rogue Waves in a Three-Dimensional Nonlinear Wavefield: A Direct Simulation-Based Approach

2009 ◽  
Author(s):  
Wenting Xiao ◽  
Yuming Liu ◽  
Dick K. P. Yue
Keyword(s):  
Nonlinear Wave ◽  
Rogue Wave ◽  
Wave Spectrum ◽  
Three Dimensional ◽  
Rogue Waves ◽  
High Order ◽  
Wave Steepness ◽  
Large Wave ◽  
Resonant Interactions ◽  
Wavefield Simulation

We describe an investigation of the occurrence, statistics, and generation mechanisms of rogue wave in the open sea using direct three-dimensional phase-resolved nonlinear wavefield simulations. To achieve this we develop an efficient nonlinear wavefield simulation capability based on the high-order spectrum method which solves the primitive phase-resolved Euler equations. The simulations account for nonlinear wave-wave interactions up to an arbitrary high order in the wave steepness and are capable of accounting for effects of bottom bathymetry, variable current, and direct physics-based models for wind input and wave breaking dissipation. We apply direct large-scale simulations to obtain a large number of phase-resolved nonlinear wavefields, initially specified by directional wave spectra. The typical spatial-temporal domain size of such numerical nonlinear wavefields is O(103 km2) over evolution time of O(hr). These spatial and temporal scales account for quartet resonant interactions and partially for quintet resonant interactions among wave components in the wavefield. From the simulated nonlinear wavefields, rogue wave events are identified and their occurrence statistics are studied. It is shown that the classic linear theory (i.e. Rayleigh distribution) significantly underestimates the rogue wave occurrence. Second-order theory improves the Rayleigh prediction, but still underestimates the rogue wave occurrence in wavefields with moderately large wave steepness and relatively narrow directional spreading and spectrum bandwidth. The influence of key wave spectrum parameters (such as significant wave height, directional spreading, effective steepness, and spectrum bandwidth) on the rogue wave occurrence is analyzed. The classification of rogue waves according to their configuration is also obtained. The key characteristics of a rogue wave or rogue wave group in terms of kinematics and surface structure are analyzed and quantified. The nonlinear wave simulations, which provide full three-dimensional kinematics and dynamics of rogue wave events, provide a powerful tool for understanding the underlying mechanisms of their generation. They are elucidated by specific examples.

Dynamics of localized waves in a (3+1)-dimensional nonlinear evolution equation

2019 ◽  
Vol 33 (09) ◽  
pp. 1950101 ◽  
Author(s):  
Yunfei Yue ◽  
Yong Chen
Keyword(s):  
Evolution Equation ◽  
Soliton Solution ◽  
Nonlinear Evolution Equation ◽  
Nonlinear Evolution ◽  
Rogue Wave ◽  
Soliton Solutions ◽  
Rogue Waves ◽  
Dark Soliton ◽  
Interaction Solutions ◽  
Localized Waves

In this paper, a (3[Formula: see text]+[Formula: see text]1)-dimensional nonlinear evolution equation is studied via the Hirota method. Soliton, lump, breather and rogue wave, as four types of localized waves, are derived. The obtained N-soliton solutions are dark solitons with some constrained parameters. General breathers, line breathers, two-order breathers, interaction solutions between the dark soliton and general breather or line breather are constructed by choosing suitable parameters on the soliton solution. By the long wave limit method on the soliton solution, some new lump and rogue wave solutions are obtained. In particular, dark lumps, interaction solutions between dark soliton and dark lump, two dark lumps are exhibited. In addition, three types of solutions related with rogue waves are also exhibited including line rogue wave, two-order line rogue waves, interaction solutions between dark soliton and dark lump or line rogue wave.

scholarly journals Modulational instability, beak-shaped rogue waves, multi-dark-dark solitons and dynamics in pair-transition-coupled nonlinear Schrödinger equations

2017 ◽  
Vol 473 (2203) ◽  
pp. 20170243 ◽  
Author(s):  
Guoqiang Zhang ◽  
Zhenya Yan ◽  
Xiao-Yong Wen
Keyword(s):  
Modulational Instability ◽  
Coupled Model ◽  
Rogue Waves ◽  
Higher Order ◽  
Nonlinear Schrödinger Equations ◽  
Schrödinger Equations ◽  
Coupled Nonlinear Schrödinger Equations ◽  
Nonlinear Schrödinger ◽  
Dark Solitons ◽  
Nonlinear Schrodinger Equations

The integrable coupled nonlinear Schrödinger equations with four-wave mixing are investigated. We first explore the conditions for modulational instability of continuous waves of this system. Secondly, based on the generalized N -fold Darboux transformation (DT), beak-shaped higher-order rogue waves (RWs) and beak-shaped higher-order rogue wave pairs are derived for the coupled model with attractive interaction in terms of simple determinants. Moreover, we derive the simple multi-dark-dark and kink-shaped multi-dark-dark solitons for the coupled model with repulsive interaction through the generalizing DT. We explore their dynamics and classifications by different kinds of spatial–temporal distribution structures including triangular, pentagonal, ‘claw-like’ and heptagonal patterns. Finally, we perform the numerical simulations to predict that some dark solitons and RWs are stable enough to develop within a short time. The results would enrich our understanding on nonlinear excitations in many coupled nonlinear wave systems with transition coupling effects.

Rogue waves in the KdV-type models

2021 ◽  
Author(s):  
Efim Pelinovsky ◽  
Anna Kokorina ◽  
Alexey Slunyaev ◽  
Tatiana Talipova ◽  
Ekaterina Didenkulova ◽  
...  
Keyword(s):  
Solitary Waves ◽  
Elastic Waves ◽  
Rogue Wave ◽  
Modulational Instability ◽  
Rogue Waves ◽  
Real Coefficient ◽  
Rigorous Results ◽  
Physical Systems ◽  
Exponential Tails ◽  
Kdv Type Equations

<p>In this study, we investigate the rogue-wave-type phenomena in the physical systems described by the Korteweg-de Vries (KdV)-like equation in the form $ u_t + [u^m \sgn{u}]_x + u_{xxx} = 0 $ with the arbitrary real coefficient $m>0$. The periodic waves (sinusoidal or cnoidal) described by this equation have been shown to suffer from the modulational instability if $m \ge 3$; the modulational growth results in the formation of rogue waves similar to the Peregrine, Kuznetsov-Ma or Akhmediev breathers known for the nonlinear Schrodinger equation. In this work we focus on the rogue wave occurrence in ensembles of soliton-type waves. First of all, the characteristics of the solitary waves are investigated depending on the power $m$. The existence of solitary waves with exponential tails, as well as algebraic solitons and compactons has been shown for different ranges of the parameter $m$ values. Their energetic stability is discussed. Two solitary wave/breathers interactions are studied as elementary acts of the soliton/breather turbulence. It is demonstrated that the property of attracting solitons/breathers is a necessity condition for the formation of rogue waves. Rigorous results are obtained for the integrable versions of the KdV-type equations. Series of numerical simulations of the rogue wave generation has been conducted for different values of $m$. The obtained results are applied to the problems of surface and internal waves in the ocean, and to elastic waves in the solid medium.</p><p>The research is supported by the RNF grant 19-12-00253.</p>

Prediction of Oceanic Rogue Waves Through Tracking Energy Fluxes

2017 ◽  
Author(s):  
Qiuchen Guo ◽  
Mohammad-Reza Alam
Keyword(s):  
Spatial Distribution ◽  
Wave Field ◽  
Spectral Method ◽  
Nonlinear Wave ◽  
Statistical Approach ◽  
Preventive Measures ◽  
Rogue Wave ◽  
Rogue Waves ◽  
Wave Fields ◽  
Weakly Nonlinear

Here, we show that location of an upcoming rogue wave can be inferred, well in advance, from spatial distribution of energy flux across the ocean surface. We use a statistical approach, and by investigating hundreds of numerical rogue wave realizations in weakly nonlinear wave fields establish a quantitative metric via which predictions can be made. Direct simulations are performed by a higher-order spectral method (HOS), and JONSWAP distribution is used to initialize the wave field. The presented metric may establish a readily achievable measure to identify turbulent locations within a sea, through which timely preventive measures can be taken to minimize damages to lives and properties.

The twin properties of rogue waves and homoclinic solutions for some nonlinear wave equations

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wei Tan ◽  
Zhao-Yang Yin
Keyword(s):  
Differential Equations ◽  
Wave Equations ◽  
Rogue Wave ◽  
Nonlinear Partial Differential Equations ◽  
Rogue Waves ◽  
Homoclinic Solutions ◽  
Nonlinear Wave Equations ◽  
Bilinear Method ◽  
Wave Solutions ◽  
Rogue Wave Solutions

Abstract The parameter limit method on the basis of Hirota’s bilinear method is proposed to construct the rogue wave solutions for nonlinear partial differential equations (NLPDEs). Some real and complex differential equations are used as concrete examples to illustrate the effectiveness and correctness of the described method. The rogue waves and homoclinic solutions of different structures are obtained and simulated by three-dimensional graphics, respectively. More importantly, we find that rogue wave solutions and homoclinic solutions appear in pairs. That is to say, for some NLPDEs, if there is a homoclinic solution, then there must be a rogue wave solution. The twin phenomenon of rogue wave solutions and homoclinic solutions of a class of NLPDEs is discussed.

Abundant rogue wave solutions for the (2 + 1)-dimensional generalized Korteweg–de Vries equation

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Huanhuan Lu ◽  
Yufeng Zhang
Keyword(s):  
Vries Equation ◽  
Rogue Wave ◽  
Rogue Waves ◽  
Third Order ◽  
First Order ◽  
Wave Solutions ◽  
De Vries ◽  
Rogue Wave Solutions ◽  
Bilinear Formulation ◽  
Hirota Bilinear

AbstractIn this paper, we analyse two types of rogue wave solutions generated from two improved ansatzs, to the (2 + 1)-dimensional generalized Korteweg–de Vries equation. With symbolic computation, the first-order rogue waves, second-order rogue waves, third-order rogue waves are generated directly from the first ansatz. Based on the Hirota bilinear formulation, another type of one-rogue waves and two-rogue waves can be obtained from the second ansatz. In addition, the dynamic behaviours of obtained rogue wave solutions are illustrated graphically.

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