Submarine Trenches and Wave-Wave Interactions Enhance the Sediment Resuspension Induced by Internal Solitary Waves

Internal solitary waves(ISWs)are nonlinear fluctuations in nature that could cause significant interactions between seawater and the seabed.ISWs have been proven to be an adequate cause of sediment resuspension in shallow and deep-sea environments.In the South China Sea,ISWs have the largest amplitude globally and directly interact with the seabed near the Dongsha slope in the northern South China Sea.We analyzed the water profile and high-resolution multibeam bathymetric data near the Dongsha slope and revealed that submarine trenches have a significant impact on the sediment resuspension by ISWs.Moreover,ISWs in the zone of the wave-wave interaction enhanced sediment mixing and resuspension.The concentration of the suspended particulate matter inside submarine trenches was significantly higher than that outside them.The concentration of the suspended particulate matter near the bottoms of trenches could be double that outside them and formed a vast bottom nepheloid layer.Trenches could increase the concentration of the suspended particulate matter in the entire water column,and a water column with a high concentration of the suspended particulate matter was formed above the trench.ISWs in the wave-wave interaction zone near Dongsha could induce twice the concentration of the bottom nepheloid layer than those in other areas.The sediment resuspension caused by ISWs is a widespread occurrence all around the world.The findings of this study can offer new insights into the influence of submarine trench and wave-wave interaction on sediment resuspension and help in geohazard assessment.

Effective regulation of the interaction process among three optical solitons

The interaction between three optical solitons is a complex and valuable research direction,which is of practical application for promoting the development of optical communication and all-optical information processing technology.In this paper,we start from the study of the variable-coefficient coupled higher-order nonlinear Schodinger equation(VCHNLSE),and obtain an analytical three-soliton solution of this equation.Based on the obtained solution,the interaction of the three optical solitons is explored when they are incident from different initial velocities and phases.When the higher-order dispersion and nonlinear functions are sinusoidal,hyperbolic secant,and hyperbolic tangent functions,the transmission properties of three optical solitons before and after interactions are discussed.Besides,this paper achieves effective regulation of amplitude and velocity of optical solitons as well as of the local state of interaction process,and interaction-free transmission of the three optical solitons is obtained with a small spacing.The relevant conclusions of the paper are of great significance in promoting the development of high-speed and large-capacity optical communication,optical signal processing,and optical computing.

A Perspective on the Evolution of Atmospheric Blocking Theories:From Eddy-Mean flow Interaction to Nonlinear Multiscale Interaction

In this paper,we first review the research advancements in blocking dynamics and highlight the merits and drawbacks of the previous theories of atmospheric blocking.Then,the dynamical mechanisms of atmospheric blocking are presented based on a nonlinear multi-scale interaction(NMI)model.Previous studies suggested that the eddy deformation(e.g.,eddy straining,wave breaking,and eddy merging)might lead to the formation and maintenance of atmospheric blocking.However,the results were speculative and problematic because the previous studies,based on the time-mean eddy-mean flow interaction model,cannot identify the causal relationship between the evolution of atmospheric blocking and the eddy deformation.Based on the NMI model,we indicate that the onset,growth,maintenance,and decay of atmospheric blocking is mainly produced by the spatiotemporal evolution of pre-existing upstream synoptic-scale eddies,whereas the eddy deformation is a concomitant phenomenon of the blocking formation.The lifetime of blocking is mainly determined by the meridional background potential vorticity gradient(PVy)because a small PVyfavors weak energy dispersion and strong nonlinearity to sustain the blocking.But the zonal movement of atmospheric blocking is associated with the background westerly wind,PVy,and the blocking amplitude.Using this NMI model,a bridge from the climate change to sub-seasonal atmospheric blocking and weather extremes might be established via examining the effect of climate change on PVy.Thus,it is expected that using the NMI model to explore the dynamics of atmospheric blocking and its change is a new direction in the future.

Super-ballistic diffusion in a quasi-periodic non-Hermitian driven system with nonlinear interaction

We investigate the effects of nonlinear interactions on quantum diffusion in a quasi-periodic quantum kicked rotor system,featuring a non-Hermitian kicking potential.Remarkably,when the non-Hermitian driving strength is sufficiently strong,the energy diffusion follows a power law of time,characterized by an exponent that decreases monotonically with increasing the strength of nonlinear interactions.This demonstrates the emergence of super-ballistic diffusion(SBD).We find a distinct prethermalization stage in the time domain preceding the onset of SBD.The unique quantum diffusion phenomena observed in this chaotic system can be attributed to the decoherence effects generated by the interplay between nonlinear interactions and the non-Hermitian kicking potential.

Quantitative analysis of soliton interactions based on the exact solutions of the nonlinear Schr?dinger equation

We make a quantitative study on the soliton interactions in the nonlinear Schro¨dinger equation(NLSE) and its variable–coefficient(vc) counterpart. For the regular two-soliton and double-pole solutions of the NLSE, we employ the asymptotic analysis method to obtain the expressions of asymptotic solitons, and analyze the interaction properties based on the soliton physical quantities(especially the soliton accelerations and interaction forces);whereas for the bounded two-soliton solution, we numerically calculate the soliton center positions and accelerations, and discuss the soliton interaction scenarios in three typical bounded cases. Via some variable transformations, we also obtain the inhomogeneous regular two-soliton and double-pole solutions for the vcNLSE with an integrable condition. Based on the expressions of asymptotic solitons, we quantitatively study the two-soliton interactions with some inhomogeneous dispersion profiles,particularly discuss the influence of the variable dispersion function f(t) on the soliton interaction dynamics.

Influence of the initial parameters on soliton interaction in nonlinear optical systems

In nonlinear optical systems,optical solitons have the transmission properties of reducing error rate,improving system security and stability,and have important research significance in future research on all optical communication.This paper uses the bilinear method to obtain the two-soliton solutions of the nonlinear Schrödinger equation.By analyzing the relevant physical parameters in the obtained solutions,the interaction between optical solitons is optimized.The influence of the initial conditions on the interactions of the optical solitons is analyzed in detail,the reason why the interaction of the optical solitons is sensitive to the initial condition is discussed,and the interactions of the optical solitons are effectively weakened.The relevant results are beneficial for reducing the error rate and promoting the communication quality of the system.

Nonlinear anisotropic finite element analysis of liquefiable tunnel–sand–pile interaction under seismic excitation

Nonlinear time‐history analysis can be used to determine the liquefiable behaviors of the tunnel-sand-pile interaction(TSPI)model with the consideration of sand anisotropy.This study presents the nonlinear response of the TSPI model with the existence of liquefaction under seismic excitation.The analysis reveals that tunnel and pile behave as isotropic elements,while sand shows isotropic,orthotropic,and anisotropic characteristics.Three constitutive models including UBC3D‐PLM(two yield surfaces associated with the hardening rule),NGI‐ADP(yielding with associated plastic potential function),and a user‐specified constitutive model are adopted to evaluate the isotropic,orthotropic,and anisotropic behaviors of sand.On this basis,two finite element‐based codes(ETABS 18.1.1 and Plaxis 3D)are used to evaluate sand behaviors and responses.Responses of the tunnel,sand,pile,and excess pore pressure ratio are recorded in the interaction zone by varying the pile diameter,tunnel diameter,and tunnel-pile clearance.Compared with the orthotropic and isotropic conditions,lower variations of results are found in the anisotropic condition,except for the case of generation of excess pore pressure.In addition,the present reanalysis results are in agreement with previous analytical and case study results,which further indicates the effectiveness of the finite element‐based numerical codes.

The Nonlinear Interaction Process in the Wave Assimilation Model and Its Experiments

This paper presents a composite interaction formula based on the discrete-interaction operator of wave-wave nonlinear interaction for deriving its adjoint source function in the wave assimilation model. Assimilation experiments were performed using the significant wave heights observed by the TOPES/POSEIDON satellite, and the gradient distribution in the physical space was also analyzed preliminarily.

Weak ENSO Asymmetry Due to Weak Nonlinear Air–Sea Interaction in CMIP5 Climate Models

State-of-the-art climate models have long-standing intrinsic biases that limit their simulation and projection capabilities. Significantly weak ENSO asymmetry and weakly nonlinear air-sea interaction over the tropical Pacific was found in CMIP5 （Coupled Model Intercomparison Project, Phase 5） climate models compared with observation. The results suggest that a weak nonlinear air-sea interaction may play a role in the weak ENSO asymmetry. Moreover, a weak nonlinearity in air-sea interaction in the models may be associated with the biases in the mean climate--the cold biases in the equatorial central Pacific. The excessive cold tongue bias pushes the deep convection far west to the western Pacific warm pool region and suppresses its development in the central equatorial Pacific. The deep convection has difficulties in further moving to the eastern equatorial Pacific, especially during extreme El Nifio events, which confines the westerly wind anomaly to the western Pacific. This weakens the eastern Pacific El Nifio events, especially the extreme E1 Nifio events, and thus leads to the weakened ENSO asymmetry in climate models. An accurate mean state structure （especially a realistic cold tongue and deep convection） is critical to reproducing ENSO events in climate models. Our evaluation also revealed that ENSO statistics in CMIP5 climate models are slightly improved compared with those of CMIP3. The weak ENSO asymmetry in CMIP5 is closer to the observation. It is more evident in CMIP5 that strong ENSO activities are usually accompanied by strong ENSO asymmetry, and the diversity of ENSO amplitude is reduced.

Analysis of spudcan-footprint interaction in a single soil with nonlinear FEM

The footprints that remain on the seabed after offshore jack-up platforms completed operations and moved out provide a significant risk for any futurej ack-up installation at that site. Detrimental horizontal and/or rotational loads will be induced on the base cone of the jack-up platform leg （spudcan） in the preloading process where only vertical loads are normally expected. However, there are no specific guidelines on design of spudcan re-installation very close to or partially overlapping existing footprints. This paper presents a rational design approach for assessing spudcan-footprint interaction and the failure process of foundation in a single layer based on nonlinear finite element method. The rela- tionship between the distance between the spudcan and the footprint and the horizontal sliding force has been obtained. Comparisons of simulation and experimental results show that the model in this paper can deal well with the combined problems of sliding friction contact, fluid-solid coupling, and convergence difficulty. The analytical results may be useful to jack-up installation workovers close to existing footprints.

Maximal and total skew information for a two-qubit system using nonlinear interaction models

Maximal and total skew information is studied. For symmetric pure states of two-qubit, they are closely related to the linear entropy, the concurrence, and the spin squeezing parameter. For a two-qubit system implemented in three nonlinear interaction models with an external field, we give the exact state vectors and the expectation value （Sz） at any time t. Based on （Sz）2, we give the maximal and the total skew information and a condition in which the maximal and the total skew information can reach 1 and 2, respectively.

Generation of breathing solitons in the propagation and interactions of Airy–Gaussian beams in a cubic–quintic nonlinear medium

Using the split-step Fourier transform method, we numerically investigate the generation of breathing solitons in the propagation and interactions of Airy–Gaussian（AiG） beams in a cubic–quintic nonlinear medium in one transverse dimension. We show that the propagation of single AiG beams can generate stable breathing solitons that do not accelerate within a certain initial power range. The propagation direction of these breathing solitons can be controlled by introducing a launch angle to the incident AiG beams. When two AiG beams accelerated in opposite directions interact with each other,different breathing solitons and soliton pairs are observed by adjusting the phase shift, the beam interval, the amplitudes,and the light field distribution of the initial AiG beams.

Diurnal wind and nonlinear interaction between inertial and tidal currents in the South China Sea during the passage of Typhoon Conson

Diurnal wind （DW） and nonlinear interaction between inertial and tidal currents near the Xisha Islands of the South China Sea （SCS） during the passage of Typhoon Conson （2010） are investigated using observational data and a damped slab model. It is found that the DWs, which are dominated by clockwise wind components, are prominent at our observational site. The DWs increase after the passage of the typhoon from 1 to about 4 m/s, which may be due to the decrease of the sea surface temperature caused by the passage of the typhoon. Kinetic energy spectra and bicoherence methods reveal nonlinear interactions between the inertial currents and the 2MK3 tidal constituent at our observational site. The slab damped model reproduces the inertial currents successfully induced by the total observed winds, and it is shown that the inertial currents induced by DWs are positively proportional to the DWs speed. Even though the observed inertial currents are distinct, the proportion of inertial currents induced by DWs to those induced by the total observed winds is just 0.7%/4% before/after the passage of typhoon. This shows that the inertial currents induced by the DWs are unimportant near the Xisha Islands during the typhoon season.

Lateral Global Buckling of Submarine Pipelines Based on the Model of Nonlinear Pipe–Soil Interaction

With the increasing development and utilization of offshore oil and gas resources, global buckling failures of pipelines subjected to high temperature and high pressure are becoming increasingly important. For unburied or semi-buried submarine pipelines, lateral global buckling represents the main form of global buckling. The pipe–soil interaction determines the deformation and stress distribution of buckling pipelines. In this paper, the nonlinear pipe–soil interaction model is introduced into the analysis of pipeline lateral global buckling, a coupling method of PSI elements and the modified RIKS algorithm is proposed to study the lateral global buckling of a pipeline, and the buckling characteristics of submarine pipeline with a single arch symmetric initial imperfection under different pipe–soil interaction models are studied. Research shows that, compared with the ideal elastic–plastic pipe–soil interaction model, when the DNV-RP-F109 model is adopted to simulate the lateral pipe–soil interactions in the lateral global buckling of a pipeline, the buckling amplitude increases, however, the critical buckling force and the initial buckling temperature difference decreases. In the DNV-RP-F109 pipe–soil interaction model, the maximum soil resistance, the residual soil resistance, and the displacement to reach the maximum soil resistance have significant effects on the analysis results of pipeline global buckling.

Maximal and total skew information of three-qubit system obtained using nonlinear interaction models

Both the maximal and the total skew information have been studied. For a three-qubit system implemented in three nonlinear interaction models, we give the exact state vector at any time t. Beused on this, we give the maximal and the total skew information. It is found that they have the same form and their evolution periods are dependent on the energy difference between the ground state and the second excited state in these models. The maximal skew information is always in the （Sx, Sv） plane. We give the condition for the occurrence of IGHZ}sy, in which they can reach the extreme values of 9/4 and 15/4, respectively. In three different decoherence channels, two kinds of information and the concurrence are calculated. We find that the phenomenon of the concurrence of sudden death occurs, but the above two kinds of information do not die suddenly. In the phase-damping channel, the two kinds of information will not be lost completely.

Second-Order Analytic Solutions of Nonlinear Interactions of Edge Waves on A Plane Sloping Bottom

Based on the full water-wave equation, a second-order analytic solution for nonlinear interaction of short edge waves on a plane sloping bottom is presented in this paper. For special ease of slope angle β = π/2, this solution can reduced to the same order solution of deep water gravity surface waves traveling along parallel coastline. Interactions between two edge waves including progressive, standing and partially reflected standing waves are also discussed. The unified analytic expressions with transfer functions for kinematic-dynamic elements of edge waves are also given. The random model of the unified wave motion processes for linear and nonlinear irregular edge waves is formulated, and the corresponding theoreti- cal autocorrelation and spectral density functions of the first and the second orders are derived. The boundary conditions for the determination of the parameters of short edge wave are suggested, that may be seen as one special simple edge wave excitation mechanism and an extension to the sea wave refraction theory. Finally some computation results are demonstrated.

An Agent Interaction Based Method for Nonlinear Process Plan Scheduling

This article puts forward a scheduling method for nonlinear process plan shop floor.Task allocation and load bal- ance are realized by bidding mechanism.Though the agent interaction process,the execution of tasks is determined and the coherence of manufacturing decision is verified.The employment of heuristic index can help to optimize the system performance.

All-optical switches based on three-soliton inelastic interaction and its application in optical communication systems

In high-speed optical communication systems,in order to improve the communication rate,the distance between pulses must be compressed,which will cause the problem of the interaction between optical pulses in optical communication systems,which has been widely concerned by researches.In this paper,the bilinear method will be used to analyze the coupled high-order nonlinear Schro¨dinger equations and obtain their three-soliton solutions.Then,the influence of the relevant parameters in the three-soliton solution on the soliton inelastic interaction is studied.In addition,the constraint conditions of each parameter in the three-soliton solution are analyzed,the inelastic interaction properties of optical solitons under different parameter conditions are obtained,and the relevant laws of the inelastic interaction of solitons are studied.The results will have potential applications in the soliton control,all-optical switching and optical computing.

LINEAR AND NONLINEAR AERODYNAMIC THEORY OF INTERACTION BETWEEN FLEXIBLE LONG STRUCTURE AND WIND

In light of the characteristics of the interactions between flexible structure and wind in three directions, and based on the rational mechanical section-model of structure, a new aerodynamic force model is accepted, i.e, the coefficients of three component forces are the functions of the instantaneous attack angle and rotational speed C-t = C-t (beta(t), 0). (i = D, L, M). So, a new method to formulate the linear and nonlinear aerodynamic items of wind and structure interacting has been put forward in accordance with 'strip theory' and modified 'quasi-static theory', and then the linear and nonlinear coupled theory of super-slender structure for civil engineering analyzing are converged in one model, For the linear aerodynamic-force parts, the semi-analytical expressions of the items so-called 'flutter derivatives' corresponding to the one in the classic equations have been given here, and so have the nonlinear parts. The study of the stability of nonlinear aerodynamic-coupled torsional vibration of the old Tacoma bridge shows that the form and results of the nonlinear control equation in rotational direction are in agreement with that of V. F. Bohm's.