Wave Characteristics Research Articles

Experimental study on the characterization of landslide-generated waves in water bodies with rigid vegetation

Considering the severe hazards posed by landslide-generated waves, the development of effective mitigation strategies is of utmost importance. This study employed physical modeling in a wave flume to investigate the characteristics of impulse waves generated by landslides in water bodies with rigid vegetation. The entry of a block slide into water produced nonlinear impulse waves within the intermediate water depth region. The results obtained validate the accuracy of the Heller and Spinneken model in predicting maximum wave amplitude and height, thereby extending its applicability to a relative slide thickness of 0.83. A novel dispersion relationship, which accounts for wave nonlinearity, is introduced in this study, offering a precise representation of the entire wave evolution process. Empirical formulas are derived to quantify the reduction in wave amplitude and height in both emergent and submerged vegetation scenarios. The study underscores the unique role of vegetation dissipation in wave attenuation, with maximum attenuation accounting for over 80% of the total reduction in emergent vegetation, in contrast to less than 67% in submerged vegetation. Furthermore, the maximum runup height of landslide-generated waves is primarily dependent on the incident wave momentum flux parameter, regardless of the vegetation arrangement patterns.

Experimental and numerical investigation of the free surface and internal wave characteristics induced by the movement of a 2D cylindrical submerged body in a stratified two-layer fluid

Experimental and numerical investigation of the free surface and internal wave characteristics induced by the movement of a 2D cylindrical submerged body in a stratified two-layer fluid

The effect of freezing temperature on the attenuation characteristics of stress waves in water-saturated granite in freezing environments

The effect of freezing temperature on the attenuation characteristics of stress waves in water-saturated granite in freezing environments

Hyperbolic Paraboloid Free-Surface Breakwaters: Hydrodynamic Study and Structural Evaluation

This study investigates the potential of hyperbolic paraboloid (hypar) shapes for enhancing wave attenuation and structural efficiency in Free-Surface Breakwaters (FSBW). A decoupled approach combining Smoothed Particle Hydrodynamics (SPH) and Finite Element Method (FEM) is employed to analyze hypar-faced FSBW performance across varying hypar warping values and wave characteristics. SPH simulations, validated through experiments, determine wave attenuation performance and extract pressure values for subsequent FEM analysis. Results indicate that hypar-faced FSBW produces increased wave attenuation compared to traditional flat-faced designs, particularly for shorter wave periods and smaller drafts. Furthermore, hypar surfaces exhibit up to three times lower principal stresses under wave loading compared to the flat counterpart, potentially allowing for thinner surfaces. The study also shows that peak-load static stress values provide a reasonable approximation for preliminary design, with less than 6% average difference compared to dynamic analysis results. In summary, this research presents hypar-faced FSBW as a promising alternative in coastal defense strategies, offering effective wave attenuation and structural efficiency in the context of rising sea levels and increasing storm intensities.

A multi-domain feature fusion epilepsy seizure detection method based on spike matching and PLV functional networks.

The identification of spikes, as a typical characteristic wave of epilepsy, is crucial for diagnosing and locating the epileptogenic region. The traditional seizure detection methods lack spike features and have low sample richness. This paper proposes a seizure detection method with spike-based phase locking value (PLV) functional brain networks and multi-domain fused features. 

Approach. In the spiking detection part, brain functional networks based on PLV are constructed to explore the changes in brain functional states during spiking discharge, from the perspective of microscopic neuronal activity to macroscopic brain region interactions. Then, in the epilepsy seizure detection task, multi-domain fused feature sequences are constructed using time-domain, frequency-domain, inter-channel correlation, and the spike detection features. Finally, Bi-LSTM and Transformer encoders and their optimized models are used to verify the effectiveness of the proposed method. 

Main results. Experimental results achieve the best seizure detection metrics on Bi-LSTM Attention, with accuracy, sensitivity, and specificity reaching 98.40%, 98.94%, and 97.86%, respectively. 

Significance. The method is significant as it innovatively applies multi channel spike network features to seizure detection. It can potentially improve the diagnosis and location of the epileptogenic region by accurately detecting seizures through the identification of spikes, which is a crucial characteristic wave of epilepsy.

Application of Near-Far Field Conversion to Measurement of Scattering on Bessel Vortex Electromagnetic Wave

The measurement and analysis of the interaction between Bessel vortex electromagnetic (EM) and several standard targets are presented in this paper. With the aid of the angular spectrum expansion (ASE) method and physics optics (PO) theorem, scattering results on the plates (metal and dielectric) and a sphere could be derived. Furthermore, plane near-field scanning and near-far field conversion methods were implemented to compare the theoretical radar cross section (RCS). In the experiment, the quasi Bessel vortex wave was generated by a holographic metasurface antenna, and the whole measurement was performed in an anechoic chamber. The results of both the theory and measurement show that the scattered fields of the plate and sphere still had characteristics of the vortex EM wave, and the scientificity and accuracy of the measured RCS were verified. Our work involved a vortex scattering experiment in the microwave frequency band, which provides strong support for the application of vortex waves in radar detection and target recognition.

Curvature Determination Method for Diverging Acoustic Lens of Underwater Acoustic Transducer.

Underwater acoustic transducers need to expand the coverage of acoustic signals as much as possible in most ocean explorations, and the directivity indicators of transducers are difficult to change after the device is packaged, which makes the emergence angle of the underwater acoustic transducer limited in special operating environments, such as polar regions, submarine volcanoes, and cold springs. Taking advantage of the refractive characteristics of sound waves propagating in different media, the directivity indicators can be controlled by installing an acoustic lens outside the underwater acoustic transducer. To increase the detection range of an underwater acoustic transducer in a specific marine environment, a curvature-determining method for the diverging acoustic lens of an underwater acoustic transducer is proposed based on the acoustic ray tracing theory. The relationship equation between the original directivity indicators of the underwater acoustic transducer and the emergence angle in the specific environment is constructed, and the slope of the acoustic lens at different positions of the underwater acoustic transducer is obtained by a progressive solution. Then, the least squares polynomial fitting of the acoustic lens slope at all the refractive positions is carried out to obtain the optimal curvature of the acoustic lens. Experiments are designed to verify the effectiveness of the curvature determination method for the diverging acoustic lens of an underwater acoustic transducer, and the directivity indicators of acoustic lenses under different materials and different marine environments are analyzed. The experimental results show that the acoustic lens can change the directivity of the underwater acoustic transducer without changing the acoustic unit array, and the curvature of the acoustic lens directly affects the directivity indicators after refraction, so the method proposed in this paper has important reference value for determining the optimal shape of the diverging acoustic lens.

Rayleigh-type wave in thermo-poroelastic media with dual-phase-lag heat conduction

Purpose The purpose of this paper is to investigate the propagation of Rayleigh-type surface wave in a porothermoelastic half-space. This study addresses the impact of surface pores characteristics, specific heat, temperature, porosity, wave frequency, types of rock frame and types of pore fluids on the propagation characteristics of Rayleigh-type wave. Design/methodology/approach A secular equation is derived, based on the potential functions for both sealed and open surface pores boundary conditions at the stress-free insulated surface of the porothermoelastic medium. Findings Propagation characteristics (velocity, attenuation and particle motions) of Rayleigh wave are significantly influenced by boundary conditions (opened or sealed surface pores) and thermal characteristics of materials. Furthermore, the path of particles throughout the propagation of Rayleigh-type waves is identified as elliptical. Originality/value A numerical example is considered to examine the effect of thermal characteristics of materials on the existing Rayleigh wave’s propagation characteristics. Graphical analysis is used to evaluate the behavior of particle motion (such as elliptical) at both open and sealed surface of the porothermoelastic medium.

Численное моделирование гидродинамических волновых процессов в Азовском море на основе ветроволновой модели WAVEWATCH III

The article is devoted to the study of the possibilities of the modern version of the third-generation wind-wave model WAVEWATCH III (WW3). The basic equations of the model are given and the software implementation is described. A retrospective analysis of the characteristics of wind waves in the Sea of Azov was carried out, and the simulation results were compared with the data from long-term observations of coastal hydrometeostations of the Sea of Azov, presented in the Unified Interdepartmental Federal Information System (ESIMO) databases. In the predictive model, the computational domains approximating the shoreline configuration and the bathymetry of real marine basins are regular latitude-longitude grids consisting of elements of size 1.2 x 1.2 degree (about 2 x 2 km). The bathymetry and the corresponding land-sea mask (a two-dimensional array with values determining the belongingness of an element to ground or sea) required to do calculations for each of the basins were constructed using navigation maps. In the retrospective analysis, climatic data for a multi-year month (2008-2023) on wind speed were used to generate input wind data at grid nodes. Based on the WW3 spectral model, the forecast of wind wave parameters in the Sea of Azov was carried out. Prognostic maps of the average period, average length and heights of the waves prevailing at different points in time were constructed. The meteorological fields (wind speed, water and air temperature) necessary for calculations were taken from the databases of the Hydrometeorological Center of Russia and NCEP/NOAA. Parallel efficiency indicators for hybrid parallelization (MPI-OpenMP) were calculated, and scalability was determined for both MPI and hybrid launches.

The Application of Terahertz Technology in Corneas and Corneal Diseases: A Systematic Review.

Terahertz (THz) waves reside in the electromagnetic spectrum between the microwave and infrared bands. In recent decades, THz technology has demonstrated its potential for biomedical applications. With the highly unique characteristics of THz waves, such as the high sensitivity to water and optimal spatial resolution coupled with the characteristics of the human cornea, such as its high water content, THz technology has been explored as a potential modality to assess corneas and corneal diseases. This systematic review provides an overview of the characteristics of THz waves, the safety profile of THz technology in the field of ophthalmology, and its clinical applications, including the objective evaluation of the corneal hydration, tear film, dry eye disease, corneal endothelium, corneal elasticity, and scarring. The paper also presents our viewpoint on the present challenges and future directions of THz technology prior to its broader integration into clinical practice.

Effect of nonlocality and surface – interface elasticity on lamb wave propagation in piezoelectric – piezomagnetic nanoplate

This study highlights the essential role of surface-interface characteristics and nonlocal elasticity in nondestructive detection for piezoelectric-piezomagnetic nanostructures. It investigates Lamb wave propagation in layered structures under nonlocal elasticity, using magnetoelectroelastic (MEE) theory with intrinsic length scales. The Gurtin–Murdoch model and generalized Young–Laplace equations incorporate surface effects in bilayer boundaries, yielding an analytical dispersion equation for EOMS conditions. Numerical results reveal the influence of surface/interface elasticity, nonlocal, and thickness parameters on dispersion. By incorporating surface and nonlocal effects, this study enhances the sensitivity and dispersion characteristics of waves, providing a deeper understanding of wave propagation in layered systems.

Design prognostics for 4400 TEU container vessel by multi‐variate Gaidai reliability approach

AbstractThis case study introduces an innovative multivariate methodology for assessing the lifetime of marine engineering systems, specifically in cargo vessel transportation. The analysis focused on stress data collected onboard a 4400 TEU container vessel during multiple trans‐Atlantic voyages. One of the major challenges in marine cargo transport lies in mitigating the risk of container loss due to excessive whipping loads. Accurate prediction of extreme stress levels on vessel deck panels remains difficult, primarily because of the nonlinear and non‐stationary nature of wave and ship motion interactions. Higher‐order dynamic effects, such as second‐ and third‐order responses, often become significant when ships operate under adverse environmental conditions, amplifying nonlinear influences. Laboratory simulations, constrained by wave characteristics and scale similarity issues, may not always provide reliable results. Consequently, data collected from vessels navigating extreme weather conditions serves as a critical resource for comprehensive container ship risk assessment. The primary goal of this study was to validate and demonstrate the effectiveness of a novel multivariate risk evaluation approach, leveraging onboard measurements of dynamic areal pressure on cargo ship deck panels as the core dataset. The Gaidai methodology for multivariate risk evaluation proved to be a robust tool for assessing failure, hazard, and damage risks in complex, nonlinear vessel deck panel and ship hull stress systems.

Propagation characteristics of stable detonation waves in curved channels with the lateral expansion effect

When a stable detonation wave propagates in a curved channel, it will be influenced by the curvature of the channel, which has been investigated in previous studies. Actually, propagation of a stable detonation wave in a curved channel becomes more unstable if the lateral expansion effect is introduced. However, this is an objective phenomenon in practical rotating detonation chambers. In order to clarify the impacts of the channel curvature and the lateral expansion on the propagation of stable detonation waves, this study has been carried out using a mixture of ethylene, oxygen, and nitrogen. The effects of the channel curvature, the detonable mixture height, and the equivalence ratio on the propagation characteristics in both confined and semi-confined curved channels have been focused in this experimental work. The propagation process was recorded by high-speed photography, and the cell width was obtained using the smoke visualization method, while the peak pressures near the outer wall were also measured. The results imply that the deficits of wave velocity and peak pressure are magnified when introducing the lateral expansion phenomenon, especially under fuel-lean and fuel-rich conditions. Meanwhile, the channel curvature and the mixture height also have a great impact on the detonation propagation. Five propagation modes have been observed after the stable detonation waves enter the curved channels with a semi-confined configuration, i.e., a stable mode, a critical mode, a weakly unstable mode, a highly unstable mode, and a deflagration mode. In addition, for the two observed unstable modes, decoupling occurs periodically near the inner wall. Finally, the critical conditions of the stable detonation mode in the semi-confined channel have been clarified. The critical inner radius should be 13.10–15.24 times of the average cell width, and meanwhile, the minimum detonable mixture height is equivalent to 7.03–8.12 times of the average cell width.

Interaction of mixed localized waves in optical media with higher-order dispersion

This work focuses on the interaction of mixed localized waves in optical media with higher-order dispersions whose dynamics are governed by a modified cubic–quintic nonlinear Schrödinger equation. For proving the integrability of this model equation, we start by building a Lax pair and an infinitely many conservation laws. Applying the linear stability analysis method, the baseband modulational instability of a stationary continuous wave solution is investigated. Studying the baseband modulational instability phenomenon, we show that the optical loss influences the instability gain spectrum: the stationary continuous wave solution under consideration satisfies the condition of the baseband modulational instability only when the optical loss is neglected. According to the generalized perturbation (n,p−n)–fold Darboux transformation, the existence and properties of the parametric first-, second-, and third-order mixed localized wave solutions for the model equation are constructed when the loss term is neglected. The built solutions helping, we engineer in optical media with higher-order dispersions new nonlinear structures showing interactions between various kinds of nonlinear waves such as multi-peak bright/dark solitons, bright/dark breathers, bright/dark rogue waves, as well as periodic waves. Graphical illustrations are then used for investigating main characteristics of the mixed localized waves propagating on vanishing/nonvanishing continuous wave background. Interestingly, our study produces nonlocal breathers in which the entire optical field oscillates periodically in conjunction with the central local oscillation during transmission. Investigating the effects of various parameters on the nonlinear structures resulting from built mixed localized wave solutions of the model equation, we show that parameter of the fourth-order dispersion can be used to describe wave compression. Also, we show that the model parameters are useful for controlling the optical waves in lossless optical media with both higher-order dispersion whose dynamics are governed by the model equation under consideration. Our results are useful for investigating mixed localized waves in nonlinear metamaterials with cubic–quintic nonlinearity, detuning intermodal dispersion, self steepening and self-frequency effects, and nonlinear third- and fourth-order dispersions.

Propagation characteristics of THz waves through magnetized dusty plasma with a ceramic substrate

The shift-operator finite-difference time-domain method is applied to investigate the transmission properties of terahertz (THz) waves through a fully ionized magnetized dusty plasma sheath with time-varying electron density distribution and a ceramic substrate. It is interesting and noteworthy that the inclusion of the ceramic layer induces a phenomenon whereby the transmissivity and reflectivity of THz waves exhibit a quasi-periodic variation with respect to frequency within the higher-frequency band (above 0.3 THz), which differs from previous reports. This result is also confirmed by the theoretical analysis, which shows that the oscillating-period of the transmissivity and reflectivity is inversely proportional to the thickness of the ceramic layer. Numerical simulations indicate that the left-hand circularly polarized waves penetrate the plasma model with a ceramic substrate more easily than the right-hand circularly polarized waves. Decreasing the electron density, plasma thickness, or dielectric constant of the ceramic leads to an increase in transmissivity. However, it is somewhat opposite when the external magnetic field strength decreases. Our findings maybe provide theoretical support for possible alleviating the issue of “blackout.”

Optical wave features and sensitivity analysis of a coupled fractional integrable system

Optical wave features and sensitivity analysis of a coupled fractional integrable system

Kinetics of the effect of the auricular heart point on the pressure-volume curve of the digital pulse

Introduction: The Heart auricular point has been shown to modify the characteristics of the digital pulse wave experimentally. However, kinetic studies have yet to widely evaluate its cardiovascular effects. The objective of this study was to propose an acukinetic model of the Heart auricular point effect using polynomial linear interpolation or spline. Methods: The digital volume pulse was recorded in healthy subjects. A photoplethysmography transducer was placed on the index finger of the right hand. The signal was modulated and amplified using the MP150 amplifier processor. A continuous 70-s recording was taken consisting of a 30-s baseline (1–30 s), a 10-s transacupuncture (31–40 s), and a 30-s post acupuncture periods (41–70 s). Participants received acupuncture at the Heart point of the right ear. The needle was inserted to a depth of approximately 3 mm, with no additional stimulation; and remained inserted for 10 s. Derivatives and integrals of each pulse cycle during transacupuncture periods were solved. The peak slope values and area under the curve of the transacupuncture period were used to construct an interpolated curve. Results: Analysis of spline curves during the transacupuncture period showed a decrease in their values in the initial period of auriculopuncture stimulation, with a recovery in the second part. These results may indicate that auriculopuncture initially reduced cardiac output, possibly causing a secondary sympathetic response mediated by baroreceptors. Conclusion: These results may indicate that auriculopuncture initially reduced cardiac output, possibly causing a secondary sympathetic response mediated by baroreceptors.

ОЦЕНКА СРЕДНЕГО ПЕРИОДА ВЕТРОВОГО ВОЛНЕНИЯ ПО ЕДИНИЧНЫМ СНИМКАМ СУДОВОГО НАВИГАЦИОННОГО РАДАРА С ПРИМЕНЕНИЕМ МЕТОДОВ ГЛУБОКОГО ОБУЧЕНИЯ

This paper presents a method for approximating the wind wave period based on ship navigation radar data in a deep learning approach. In this work, a convolutional neural network ResNet is applied, which processes radar images and approximates the values of the wind wave period. The study evaluates the errors of the method in the measure of the standard deviation of the neural network compared to the values measured by the Spotter wave buoy, which allows us to assess the quality of the proposed algorithm. The results demonstrate the efficiency of using neural networks to approximate wave characteristics from radar image data.

Time–frequency characteristics and influencing factors of the pressure wave caused by power–frequency arc inside a closed oil tank

AbstractThe arc faults inside oil‐immersed power equipment can produce high‐amplitude pressure waves inside tanks, which might cause ignition and explosion accidents. This kind of failure is one of the most severe faults for power equipment and has attracted considerable attention in recent years. However, due to the high risk of the experiments and the complex development of arc in oil, the characteristics of the pressure wave formed by the arc are still confusing. In this paper, the time–frequency characteristics of pressure waves are analysed using several experiments of 1–8 kA power–frequency arc inside a closed oil tank. The experimental results show that the pressure wave produced by the arc in oil contains three frequency bands, 0–500 Hz, 500 Hz–40 kHz, and above 40 kHz, which are related to the arc energy, the average current around arc ignition and the metal wire explosion respectively. This helps further understand the formation mechanism of the pressure wave caused by the arc in oil. This paper discusses the influences of ignition wire on arc‐formed pressure waves. A wire diameter selection method for arc experiments is established to reduce the pressure differences between wire‐ignited arcs and actual arc faults.

Modeling the Two‐Dimensional Propagation of Whistler‐Mode Chorus Waves in the Magnetic Peaks

AbstractRecent studies have shown that chorus waves can be guided by magnetic peaks based on one‐dimensional theories and simulations. Despite these findings, such ducting propagation within the inner magnetosphere remains unconfirmed. In this research, we conduct detailed ray tracing simulations to explore the two‐dimensional behavior of chorus waves in regions characterized by magnetic peaks. Our findings demonstrate that chorus waves can indeed be guided by magnetic peaks, undergoing repeated reflections on both sides of the peak. Additionally, we discuss the physical mechanisms responsible for these repetitive reflections, offering deeper insights into the process. To further enrich our analysis, we performed a parameter analysis to study how different wave frequencies and initial locations influence the propagation characteristics of chorus waves. The results provide a more comprehensive understanding of how whistler‐mode waves propagate within the magnetosphere, enhancing our knowledge of wave‐particle interactions and the dynamics of space plasma environments.