Physica D: Nonlinear Phenomena最新文献

{"title":"Characterizing temporal correlations in the output of a semiconductor laser with optical feedback","authors":"María Duque-Gijón ,&nbsp;Jordi Tiana-Alsina ,&nbsp;Cristina Masoller ,&nbsp;Andrés Aragoneses","doi":"10.1016/j.physd.2025.134760","DOIUrl":"10.1016/j.physd.2025.134760","url":null,"abstract":"<div><div>We perform an experimental study of the dynamics of a semiconductor laser with optical feedback. We use two event-based methods to characterize the time series of the emitted intensity, one based on events that are defined by threshold-crossings (we refer to this method as spikes analysis), and the other one on events that are defined by intensity minima that are below a threshold (we refer to this method as peak analysis). By applying ordinal analysis to sequences of time intervals between consecutive events, we identify temporal correlations in the timing of the events that vary with the method used to define the events, as well as with the experimental control parameters, the laser pump current and feedback strength. The events defined by spike analysis are usually slower than those defined by peak analysis (their frequencies depend on the experimental conditions and are typically <span><math><mrow><mo>≈</mo><mn>10</mn></mrow></math></span> MHz and <span><math><mrow><mo>≈</mo><mn>1</mn></mrow></math></span> GHz respectively). We show that the two methods used to define events in the intensity time series provide a complementary characterization of the dynamics. We also find, with the two methods and in broad parameter regions, that the ordinal probabilities are organized in clusters formed by pairs of probabilities with similar values. We propose three diagnostic tools to analyze the clustering of the ordinal probabilities.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134760"},"PeriodicalIF":2.7,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of convergence angle of Ranque-Hilsch vortex tube on the optimization of thermal separation in compressible swirl flow","authors":"Kannan Shaji ,&nbsp;Vinod Narayanan ,&nbsp;Abhilash Suryan ,&nbsp;Heuy Dong Kim","doi":"10.1016/j.physd.2025.134761","DOIUrl":"10.1016/j.physd.2025.134761","url":null,"abstract":"<div><div>Ranque-Hilsch vortex tube is a highly efficient fluidic expansion device with thermal separation features. Geometric optimization of the device is necessary for getting the best performance. Current study aims to conduct a validated and comparative analysis of the significance of angle of convergence in a convergent vortex tube compared to a straight tube design. Numerical simulations of the swirl flow field are performed to maximize thermal separation. The result shows a strong correlation between swirl flow intensity distribution and vortex tube convergence angle, suggesting that adjusting the angle can remodel vortex core to improve temperature separation. The occurrence and analysis of the bifurcation point confirm the critical angle of convergence, where optimal temperature separation occurs most effectively and efficiently. Exergy and enthalpy-entropy analyses validate the design features, indicating a reduction in cold exit flow irreversibility when the design features critical convergence angle. Further studies are warranted for a comprehensive optimization of the design.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134761"},"PeriodicalIF":2.7,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plane-symmetric capillary turbulence: Five-wave interactions","authors":"E.A. Kochurin ,&nbsp;P.A. Russkikh","doi":"10.1016/j.physd.2025.134763","DOIUrl":"10.1016/j.physd.2025.134763","url":null,"abstract":"<div><div>The theory of isotropic capillary turbulence was developed in the late 1960s by Zakharov and Filonenko. To date, the analytical solution of the kinetic equation describing the stationary transfer of energy to small scales due to three-wave resonant interactions, called the Zakharov–Filonenko spectrum, has been confirmed with high accuracy. However, in the case of strong anisotropy in wave propagation, where all waves are collinear, the situation changes significantly. In such a degenerate geometry, the conditions of resonant interaction cease to be fulfilled not only for three waves, but also for four interacting waves. In this work, we perform fully nonlinear simulations of plane-symmetric capillary turbulence. We demonstrate that the system of interacting waves evolves into a quasi-stationary state with a direct energy cascade, despite the absence of low-order resonances. The calculated spectra of surface elevations are accurately described by analytical estimates derived dimensionally under the assumption of the dominant influence of five-wave resonant interactions. A detailed study of the statistical characteristics of the weakly turbulent state does not reveal the influence of any coherent or strongly nonlinear structures. The performed high-order correlation analysis indicates a variety of non-trivial five-wave resonances. We show that the process of wave decay into two pairs of counter-propagating waves is responsible for the local energy transfer to small scales. Overall, the calculation results are in good agreement with both the weak turbulence theory and recent experiments made by Ricard and Falcon.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134763"},"PeriodicalIF":2.7,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144262101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear structures in laboratory and space dusty plasmas","authors":"L.M. Zelenyi ,&nbsp;S.I. Popel","doi":"10.1016/j.physd.2025.134721","DOIUrl":"10.1016/j.physd.2025.134721","url":null,"abstract":"<div><div>A brief review of studies on nonlinear wave structures in dusty plasmas is presented, for which effects that appear specifically in dusty plasmas, for example, anomalous dissipation associated with the processes of dust particle charging, are presented. Examples of such structures in laboratory and space plasmas are given. In particular, a description is presented of the experiments at the Institute of Space and Astronautical Sciences (Japan) and at the University of Iowa (USA). A significant accent is made to space research, namely, the formation of bow shock arising from the interaction of the comet’s dust coma and the solar wind, and the formation of a nonlinear structure in the region of the lunar terminator.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134721"},"PeriodicalIF":2.7,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144254808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rigorous convergence bounds for stochastic differential equations with application to uncertainty quantification","authors":"Liam A.A. Blake,&nbsp;John Maclean,&nbsp;Sanjeeva Balasuriya","doi":"10.1016/j.physd.2025.134742","DOIUrl":"10.1016/j.physd.2025.134742","url":null,"abstract":"<div><div>Prediction via continuous-time models will always be subject to model error, for example due to unexplainable phenomena, uncertainties in any data driving the model, or discretisation/resolution issues. In this paper, we consider a general class of stochastic differential equations and provide rigorous convergence bounds to an analytically solvable approximation. We provide the explicit convergence rate for all moments of a fully non-autonomous model with both multiplicative noise and uncertain initial conditions. Our second main contribution is to extend stochastic sensitivity, a recently introduced uncertainty quantification tool, to arbitrary dimensions and provide a new calculation method that empowers rapid computation. We demonstrate the power and adaptability of our contributions on a diverse set of numerical examples in 1-, 2-, 3-, and 4-dimensions, including providing stochastic sensitivity calculations for an idealised eddy parameterisation of the Gulf Stream.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134742"},"PeriodicalIF":2.7,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144222000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-to-one internal resonances between acoustic and optical waves in metamaterials with nonlinear resonators","authors":"Laura Di Gregorio,&nbsp;Walter Lacarbonara","doi":"10.1016/j.physd.2025.134748","DOIUrl":"10.1016/j.physd.2025.134748","url":null,"abstract":"<div><div>We investigate the modal interactions between two generalized oscillators representing the acoustic and optical waves obtained as solutions of the wave propagation equations across a metamaterial conceived as cellular hosting 2D structure augmented by intracellular resonators. Without damping, the system is Hamiltonian, with the origin as an elliptic equilibrium characterized by two distinct linear frequencies. To understand the underlying dynamics, it is crucial to derive explicit analytical formulae for the nonlinear frequencies as functions of the physical parameters. In the small amplitude regime (perturbative case), we provide the first-order nonlinear correction to the linear frequencies. While this analytic expression was already derived for non-resonant cases, the interest is here placed on wave interactions in the context of resonant or nearly resonant scenarios. In particular, we focus on 3:1 internal resonance, the only resonance involved in the first-order correction. We then address the challenging strongly resonant case in which the detuning is small with respect to the perturbative parameter. Unlike standard approaches, here we capture the full complexity of resonant dynamics, revealing a richer, more intricate topological features. Utilizing the Hamiltonian structure, we employ Perturbation Theory to transform the system into Birkhoff Normal Form up to order four. This involves converting the system into action–angle variables, where the truncated Hamiltonian at order four depends on the actions and, due to the resonance, on one “slow” angle. By constructing suitable nonlinear and not close-to-the-identity coordinate transformations, we identify new sets of symplectic action–angle variables. In these variables, the resulting system is integrable up to higher-order terms, meaning it does not depend on the angles, and the frequencies are obtained from the derivatives of the energy with respect to the actions. This construction is highly dependent on the physical parameters, necessitating a detailed case analysis of the phase portrait, which reveals up to six topologically distinct behaviors. In each instance, we describe the nonlinear normal modes (elliptic/hyperbolic periodic orbits, invariant tori) and their stable and unstable manifolds of the truncated Hamiltonian. For the computations, we examine resonant wave interactions in metamaterial honeycombs with periodically distributed Duffing-type resonators, specifically addressing the nonlinear effects on the bandgap. More precisely, in view of the metamaterial design, our analysis allows one to identify the values of the modal mass and stiffness of the resonators, that maximize the beneficial effect of nonlinearity in enlarging the bandgap width.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134748"},"PeriodicalIF":2.7,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144194493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A simple three-component mixing problem for the evaluation of a new reaction rate model","authors":"Brandon E. Morgan,&nbsp;Kevin Ferguson","doi":"10.1016/j.physd.2025.134718","DOIUrl":"10.1016/j.physd.2025.134718","url":null,"abstract":"<div><div>A simple computational mixing problem is presented which can be utilized to assess the behavior of Reynolds-averaged reaction rate models in a problem with temporally varying mixedness. In this problem, three mixing components are homogeneously distributed but initially separated in a triply periodic domain. These components are initialized within a Taylor–Green-like velocity field, which creates a mixing history evolving from the so-called “no-mix limit” to a well-mixed state. Large-eddy simulation results from this problem in configurations involving both premixed and nonpremixed reactants are then compared with zero-dimensional Reynolds-averaged Navier–Stokes results utilizing a new model for multicomponent reacting mixtures. The new model is shown to appropriately respect the no-mix limit and outperforms an earlier model (Morgan, 2022), particularly at early times when components are near the no-mix limit.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134718"},"PeriodicalIF":2.7,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144205398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analytical properties of Stoyanov step bunches: Solutions, scaling, stationary profiles","authors":"Vassil Ivanov","doi":"10.1016/j.physd.2025.134755","DOIUrl":"10.1016/j.physd.2025.134755","url":null,"abstract":"<div><div>Within the framework of the Stoyanov–Tonchev equation, which describes the surface height evolution during the vicinal sublimation process affected by the electromigration of the adatoms, we explore further the stationary profiles of step bunches towards obtaining a closed-form solution. For this particular case, we derive an explicit analytical result for the slope-height relation for the bunches, and many of the well-known scaling results for the height and width of the bunch. A novel analytical approximation for the bunch profile <span><math><mrow><mi>h</mi><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span> is derived, leading to a scaling relation for the minimal step-step distance in the bunch formed as a product of two parts - a special combination of the initial parameters, with the dimension of length, and a complementary one that contains only the number of steps in the bunch.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134755"},"PeriodicalIF":2.7,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel underwater weak signal detection method based on High-order double-coupled duffing oscillator, Empirical wavelet transform and Hilbert transform","authors":"Yupeng Shen ,&nbsp;Zhe Chen ,&nbsp;Yaan Li ,&nbsp;Weijia Li","doi":"10.1016/j.physd.2025.134775","DOIUrl":"10.1016/j.physd.2025.134775","url":null,"abstract":"<div><div>The increasing complexity of marine noise environments and advancements in stealth technology have significantly weakened the continuous spectrum of underwater signals, rendering traditional random signal analysis methods inadequate for weak signal detection amidst complex noise backgrounds. To address the challenge of detecting underwater weak signals at ultra-low Signal-to-Noise Ratios (SNR), we propose a novel detection method that integrates high-order double-coupled Duffing oscillator, Empirical Wavelet Transform (EWT), and Hilbert Transform. This approach begins with the introduction of a novel high-order double-coupled Duffing oscillator, whose dynamic behavior is thoroughly analyzed using nonlinear techniques, including Lyapunov exponents, bifurcation analysis, and entropy measures. The analysis proves that the improved Duffing oscillator has excellent robustness to different noise. Then, combined with the constructed geometric frequency array and the scale transformation, a new weak signal detection array that can detect any frequency is constructed. The system discerns the presence of underwater signals by monitoring changes in the attractor trajectory, specifically transitions from chaotic behavior to large-period or intermittent chaos. Finally, a novel frequency extraction method that leverages EWT and Hilbert Transform is proposed, which can achieve noise reduction and kurtosis optimization for intermittent chaotic signals, thereby extracting the actual frequency of underwater weak signals. Experimental results confirm that the proposed detection array effectively identifies underwater weak signals submerged in complex noise environments, achieving a detection SNR of -38.42 dB and an extracted signal frequency error of &lt;1 %. The simulation results meet the stringent accuracy requirements for underwater sonar applications.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134775"},"PeriodicalIF":2.7,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144221999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear stability and instability of plasma boundary layers","authors":"Masahiro Suzuki ,&nbsp;Masahiro Takayama ,&nbsp;Katherine Zhiyuan Zhang","doi":"10.1016/j.physd.2025.134743","DOIUrl":"10.1016/j.physd.2025.134743","url":null,"abstract":"<div><div>We investigate the formation of a plasma boundary layer (sheath) by considering the Vlasov–Poisson system on a half space with the completely absorbing boundary condition. In Suzuki and Takayama (2023), the solvability of the stationary problem is studied. In this paper, we study the nonlinear stability and instability of these stationary solutions of the Vlasov–Poisson system.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134743"},"PeriodicalIF":2.7,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144205651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}