Wave Breaking Research Articles

Scanning tunneling microscopy study on symmetry breaking of charge density wave in FeGe

Scanning tunneling microscopy study on symmetry breaking of charge density wave in FeGe

Fully Nonlinear Interaction of Water Waves and a Submerged Cylinder With Wave Breaking Detection and Suppression

Abstract In this paper, the nonlinear interaction of regular water waves propagating over a fixed and submerged circular cylinder is numerically studied. At the structure’s lee side, the free surface profile experiences strong nonlinear deformation where the superharmonic free wave generated can be significant and is superposed on the transmitted wave. The wave profile then becomes asymmetric and skewed and may eventually reach the point of physical wave breaking. The governing equation and boundary conditions of this wave–structure interaction problem are formulated using both the fully nonlinear and the weak-scatterer theory. The corresponding boundary value problem is numerically solved by the immersed-boundary adaptive harmonic polynomial cell solver. In this study, a pragmatic wave-breaking suppression model is incorporated into the original solver. Both the harmonic free wave amplitudes at the structure’s lee side and the harmonic vertical forces on the cylinder are studied. The simulated harmonic wave amplitudes are compared to other published experiments and theoretical data. In general, good agreement is achieved. The effects of the incorporated wave-breaking suppression model on the simulated results are discussed. In our study, the incorporation of the pragmatic wave-breaking suppression model successfully extends the capabilities of the original fully nonlinear immersed-boundary adaptive harmonic polynomial cell solver.

Thermal Variability in the Martian Upper Atmosphere within the Crustal Magnetic Field Region Induced by Gravity Wave Dissipation Due to Ion-drag Effect

Abstract Mars Atmosphere and Volatile Evolution detected a significant temperature increase of approximately 20–40 K in the upper atmosphere within the strong crustal magnetic field (CF) region during two deep dip campaigns. Previous studies were unable to fully explain this thermal variation. Atmospheric gravity waves are an underlying mechanism, attributed to the ion-drag effect. During this effect process, the collisions between neutral particles and ions transfer wave momentum along the magnetic field lines, and lead to wave dissipation and energy release to heat or cool the background atmosphere. We developed a one-dimensional linear wave model to describe the effect of ion-drag on wave propagation and dissipation in the Martian upper atmosphere. Our results show that the ion-drag effect influences wave propagation primarily above 160 km in the CF region and around 200 km in the noncrustal magnetic field (NCF) region. The total wave energy flux driven by the ion-drag effect in the CF region is approximately 108 eV cm−2 s−1, with heating rates of 10–60 K per sol and cooling rates up to 40 K per sol above 155 km. Wave-driven temperature enhancements in the CF region due to the ion-drag effect are a few Kelvins higher than in the NCF regions, though still smaller than the observed 20–40 K. Additional wave processes, including wave breaking and multiwave dissipation, may contribute to the observed thermal variability and should be considered in future studies.

Evolution of autoresonant plasma wave excitation in two-dimensional particle-in-cell simulations

The generation of an autoresonantly phase-locked high-amplitude plasma waves to the chirped beat frequency of two driving lasers is studied in two dimensions using particle-in-cell simulations. The two-dimensional plasma and laser parameters correspond to those that optimized the plasma wave amplitude in one-dimensional simulations. Near the start of autoresonant locking, the two-dimensional simulations appear similar to one-dimensional particle-in-cell results (Luo et al., Phys. Rev. Res., vol. 6, 2024, p. 013338) with plasma wave amplitudes above the Rosenbluth–Liu limit. Later, just below wave breaking, the two-dimensional simulation exhibits a Weibel-like instability and eventually laser beam filamentation. These limit the coherence of the plasma oscillation after the peak plasma wave field is obtained. In spite of the reduction of spatial coherence of the accelerating density structure, the acceleration of self-injected electrons in the case studied remains at $70\,\%$ to $80\,\%$ of that observed in one dimension. Other effects such as plasma wave bowing are discussed.

Vertical ozone transport by Rossby wave breaking in upper troposphere-lower stratosphere is weakening

Vertical ozone transport by Rossby wave breaking in upper troposphere-lower stratosphere is weakening

The impact of transience in the interaction between orographic gravity waves and mean flow

Abstract A Lagrangian gravity-wave parameterization (MS-GWaM, Multi-Scale Gravity-Wave Model) that allows for fully transient wave-mean-flow interaction and horizontal propagation is applied to orographic gravity waves for the first time. Both linear and nonlinear mountain waves are modeled in idealized simulations within the pseudo-incompressible flow solver PincFlow. Two-dimensional flows over monochromatic orographies are considered, using MS-GWaM either in its fully transient implementation or in a steady-state implementation that represents classic mountain-wave parameterizations. Comparisons of wave-resolving simulations (not using MS-GWaM) and coarse-resolution simulations (using MS-GWaM) show that allowing for transience leads to a significantly more accurate forcing of the resolved mean flow. The parameterization is able to reproduce the transient forcing of linearly generated mountain waves that slowly propagate upwards, in contrast to the instantaneous distribution of wave energy in classic parameterizations. At high altitudes, wave breaking induces a wind reversal that is captured by the transient parameterization but inhibited in steady-state simulations, due to the assumption of critical level formation. This shows that transience can have a substantial impact in the interaction between mountain waves and mean flow.

The Role of Vortex Preconditioning in the Occurrence of Antarctic Weak Polar Vortex Events

Abstract The Antarctic weak polar vortex events (WPVs) can induce noticeable impacts on the tropospheric circulation. The vortex preconditioning refers to the anomalous stratospheric state favoring the occurrence of vortex disruption. Motivated by the limited research on the stratospheric preconditioning of Antarctic WPVs, the detailed role of preconditioned stratospheric anomalies in triggering WPVs is investigated, using the latest ERA5.1 reanalysis data. The vortex preconditioning of WPVs originates from the planetary wave breaking in the middle-upper stratosphere. It features a poleward shift of the polar night jet that occurs within 80 days before the onset of WPVs, coinciding with the sharpening of meridional potential vorticity (PV) gradient along the vortex edge. Our results indicate that the stratospheric modulation during vortex preconditioning is the essential factor for triggering most Antarctic WPVs, regardless of the presence of an anomalously strong wave source in the troposphere. About 84% of WPVs are preceded by robustly positive meridional PV gradient anomalies along the vortex edge. Furthermore, about 36% of WPVs are only preceded by strong stratospheric anomalies but without anomalously strong tropospheric wave pulse. Compared to the Northern Hemisphere, preconditioned stratospheric signals in the Southern Hemisphere have a longer duration and larger proportion linking to WPVs. More Antarctic WPVs are preceded by more frequency wave-1 minor warming-like disturbances in the middle-upper stratosphere than Arctic WPVs. Especially, the stratospheric indicator can at least account for about 41% and 65% magnitudes of 10-day zonal-wind deceleration for the two consensus Antarctic WPVs in 2002 and 2019, respectively.

Performance Assessment of a Coupled Circulation–Wave Modelling System for the Northwest Atlantic

We present a modified version of a coupled circulation–wave modelling system for the northwest Atlantic (CWMS-NWA) by including additional physics associated with wave–current interactions. The latest modifications include a parameterization of Langmuir turbulence and surface flux of turbulent kinetic energy from wave breaking in vertical mixing. The performance of the modified version of CWMS-NWA during Hurricane Arthur in 2014 is assessed using in situ measurements and satellite data. Several error statistics are used to evaluate the model performance, including correlation (R), root mean square error (RMSE), normalized model variance of model errors (γ2) and relative bias (RB). It is found that the simulated surface waves (R ≈ 94.0%, RMSE ≈ 27.5 cm, γ2≈ 0.16) and surface elevations (R ≈ 97.3%, RMSE ≈ 24.0 cm, γ2≈ 0.07) are in a good agreement with observations. The large-scale circulation, hydrography and associated storm-induced changes in the upper ocean during Arthur are reproduced satisfactorily by the modified version of CWMS-NWA. Relative to satellite observations of the daily averaged sea surface temperature (SST), the model reproduces large-scale features as demonstrated by the error metrics: R ≈ 97.8%, RMSE ≈ 1.6 ∘C and RB ≈ 8.6 ×10−3∘C.

Contrasting the Intraseasonal Precipitation in the Western and Eastern North Pacific During Boreal Winter

AbstractThe wintertime North Pacific exhibits two types of intraseasonal periodicity in daily precipitation, with a period of 10–20 and 30–90 days in the western and eastern North Pacific. This study aims to identify and compare characteristics and mechanisms of intraseasonal precipitation in these two regions using daily observational data. Our results indicate their notable differences in atmospheric circulations and dynamical processes, despite similarities in moisture sources. A wave train associated with the intraseasonal precipitation in the western North Pacific characterized by anomalous cyclones and anticyclones from West Siberia into the North Pacific is observed, accompanied by anomalous wave activity. By diagnosing local finite‐amplitude wave activity (LWA) budget, we demonstrate that the baroclinic eddy generation initiates the upstream growth of wave activity, whereas its downstream development is primarily attributed to the zonal advection of wave train. The upstream wave train induces barotropic and baroclinic instabilities in Kuroshio‐Oyashio extension (KOE). In contrast, the anomalous atmospheric circulations related to intraseasonal precipitation in the eastern North Pacific feature a tripolar structure, with downstream propagation of wave activity from the eastern North Pacific to the North American continent. Diabatic heating, along with local eddy generation, contributes to the upstream growth of wave activity. Residual term, possibly linked to the wave activity dissipation associated with wave breaking, extends the wave activity downstream. Thermal and baroclinic instabilities, associated with the diabatic heating and local eddy generation, create favorable conditions for the precipitation. This study may contribute to the improvement of intraseasonal precipitation prediction over the pan‐North Pacific region.

SFY — A lightweight, high-frequency and phase-resolving wave-buoy for coastal waters

Abstract Small lightweight wave buoys, SFYs, designed to operate near the coast, have been developed. The buoys are designed to record and transmit the full time series of surface acceleration at 52 Hz. The buoy uses the cellular network to transfer data and position (up to 80 km from the base station). This reduces costs and increases band-width. The low cost and low weight permits the buoys to be deployed easily, and in arrays in areas where satellite and wave models struggle to resolve wave and current interaction. The buoys are tested in a wave-flume, the open water and in the breaking waves of the surf. The conditions range from calm to significant wave heights exceeding 7 m and crashing breakers with accelerations exceeding 10g. The high sample rate captures the impulse of breaking waves, and allows them to be studied in detail. Breaking waves are measured and quantified in the open water. We measure breaking waves in the surf and recover the trajectory of waves breaking in the field to a higher degree than previously done. The time series of surface elevation, and accurate positioning, permits the signal of adjacent buoys to be correlated in a coherent phase-resolved way. Finally, we offer an explanation and solution for the ubiquitous low-frequency noise in IMU-based buoys and discuss necessary sampling and design to measure in areas of breaking waves.

A Short Review of Strategies for Augmenting Organism Recruitment on Coastal Defense Structures

The global demand for coastal urbanization is rising with the increasing population. Alas, living close to the ocean threatens human endeavors with high currents, waves, and increasing storm frequency. Accordingly, the need for more coastal defense structures (CDSs) rises. Structures built from complex units meant to prevent and/or mitigate coastal erosion and floods, additionally providing wave protection or wave attenuation, are constructed on and near natural habitats where they alter local ecosystems. Traditional CDSs mostly fail to harbor diverse and abundant communities. However, this can be changed by eco-friendly methodologies and designs that are being tested and implemented to improve CDSs’ ecological value. Some of these can be implemented during the construction period, while others can fit on existing structures, such as wave breakers and seawalls. Effective methods include augmenting surface rugosity through strategic perforations, integrating artificial panels for increased complexity, implementing soft (naturally based) engineering solutions such as geotextiles, replacing industrial concrete mixtures for CDS construction with “green concrete” and ecologically friendly mixtures, and using alternative, eco-friendly units in CDS erections. In this mini review, we suggest that by integrating sustainable practices into coastal development, we can significantly mitigate the ecological damage caused by traditional CDSs and promote more harmonious relationships between human construction and the marine environment. This shift towards environmentally conscious coastal defenses is essential and a responsibility for ensuring the long-term sustainability of our coastal communities and the health of our oceans. We present current methodologies used on breakwaters worldwide.

Wave-breaking phenomena around a wedge-shaped bow

Bow wave breaking has long been a research challenge in the research field of ship hydrodynamic. This study simplifies the ship's bow as a three-dimensional wedge-shaped structure and conducts experimental measurements to investigate the dynamic characteristics of bow wave breaking. The experiments are carried out in a recirculating water channel, with the force transducer and wave height probes used for measurement. The complex mechanisms influencing bow wave breaking in real-world scenarios can be influenced by factors such as flow velocity, draft, flooding angle, flare angle, and yaw angle. Experiments are carried out under various conditions by controlling one factor at a time. The results show that more intense wave breaking not only increases the resistance force on the wedge but also raises the wave height of the measuring point in the non-breaking region and the nonlinearity in the breaking region. The high-frequency fluctuations of wave height in the breaking region become more obvious. Through a quantitative comparison of different factors on the wave-breaking phenomena, it can be found that the flooding angle has a significant impact on resistance, which helps explain why slender hull designs are commonly used for fast ships. The yaw angle plays a crucial role in affecting the bow waves, influencing both stable wave height and nonlinear breaking waves. The measurement results presented in this paper can provide valuable validation data and flow insights for studies on ship bow wave breaking.

Dataset of polarimetric images of mechanically generated water surface waves coupled with surface elevation records by wave gauges linear array.

Effective spatio-temporal measurements of water surface elevation (water waves) in laboratory experiments are essential for scientific and engineering research. Existing techniques are often cumbersome, computationally heavy and generally suffer from limited wavenumber/frequency response. To address these challenges a novel method was developed, using polarization filter equipped camera as the main sensor and Machine Learning (ML) algorithms for data processing [1,2]. The developed method training and evaluation was based on in-house made supervised dataset. Here we present this supervised dataset of polarimetric images of the water surface coupled with the water surface elevation measurements made by a linear array of resistance-type wave gauges (WG). The water waves were mechanically generated in a laboratory waves basin, and the polarimetric images were captured under an artificial light source. Meticulous camera and WGs calibration and instruments synchronization supported high spatio-temporal resolution. The data set covers several wavefield conditions, from simple monochromatic wave trains of various steepness, to irregular wavefield of JONSWAP prescribed spectral shape and several wave breaking scenarios. The dataset contains measurements repeated in several camera positions relative to the wave field propagation direction.

Wave dissipation performance of breakwater

This paper conducts a comprehensive review of the wave dissipation performance of various types of breakwaters in marine engineering. Over time, breakwaters have undergone significant evolution, and modern ones are constructed using advanced materials to enhance the efficiency of wave energy dissipation. They can be categorized into vertical, sloped, floating, and permeable types, each possessing distinct wave dissipation characteristics, physical principles, advantages, and disadvantages. Vertical breakwaters primarily reflect wave energy but can potentially cause strong reflections, which may have adverse effects in certain areas. Sloped breakwaters utilize the principles of kinetic energy conversion and wave breaking to dissipate energy, making them suitable for a wide range of coastal conditions. Floating breakwaters offer flexibility and adjustability to different wave conditions, while permeable breakwaters allow for water exchange while still reducing wave energy, which is beneficial for maintaining the ecological balance of the coastal area. The choice of breakwater type depends on factors such as wave conditions, topography, and environmental impact. In the future, breakthroughs in materials, design, and technology are anticipated to improve the performance of breakwaters. The selection and combination of breakwater types should take into account local conditions and requirements to ensure the effective protection of coastlines and marine facilities.

A One-Dimensional Model for Investigating Scale-Separated Approaches to the Interaction of Oceanic Internal Waves

Abstract High-frequency wave propagation in near-inertial wave shear has, for four decades, been considered fundamental in setting the spectral character of the oceanic internal wave continuum and for transporting energy to wave breaking. We compare idealized ray-tracing numerical results with metrics derived using a wave turbulence derivation for the kinetic equation and a path integral to study this specific process. Statistical metrics include the time-dependent ensemble mean vertical wavenumber, referred to as a mean drift; dispersion about the mean drift; time-lagged correlation estimates of wavenumber; and phase locking of the wave packets with the background. The path integral permits us to identify the mean drift as a resonant process and dispersion about that mean drift as nonresonant. At small inertial wave amplitudes, ray tracing, wave turbulence, and the path integral provide consistent descriptions for the mean drift of wave packets in the spectral domain and dispersion about the mean drift. Extrapolating these results to the background internal wavefield overpredicts downscale energy transports by an order of magnitude. At oceanic amplitudes, however, the numerics support diminished transport and dispersion that coincide with the mean drift time scale becoming similar to the lagged correlation time scale. We parse this as the transition to a non-Markovian process. Despite this decrease, numerical estimates of downscale energy transfer are still too large. We argue that residual differences result from an unwarranted discard of Bragg scattering resonances. Our results support replacing the long-standing interpretive paradigm of extreme scale-separated interactions with a more nuanced slate of “local” interactions in the kinetic equation.

Break Wave Lithotripsy for Urolithiasis: Results of the First-in-Human International Multi-Institutional Clinical Trial: Erratum.

Break Wave Lithotripsy for Urolithiasis: Results of the First-in-Human International Multi-Institutional Clinical Trial: Erratum.

Numerical study of soliton behavior of generalised Kuramoto-Sivashinsky type equations with Hermite splines

<p>The traveling wave behavior of the nonlinear third and fourth-order advection-diffusion equation has been elaborated. In this study, the effect of dispersion and dissipation processes was mainly analyzed thoroughly. In the thorough analysis, strictly permanent short waves to breaking waves, having comparative higher amplitudes, have been observed. The governed problem was employed with the space-splitting method for a coupled system of equations to conduct the computational process. For the time derivative, the Crank-Nicolson difference approximation was studied. An orthogonal collocation method using Hermite splines has been implemented to approximate the solution of the semi-discretized coupled problem. The proposed method reduces the equation to an iterative scheme of an algebraic system of collocation equations, which reduced the computational complexity. The proposed scheme is found to be unconditionally stable, and the numerical demonstrations and comparisons represented the computational efficiency.</p>

Validation of an efficient two-layer non-hydrostatic wave model on a sloping foreshore

In the physical modelling of coastal engineering problems, use is often made of foreshores and transition slopes to obtain the desired wave conditions - both spectral parameters and wave height distribution - at a given location. Numerical wave models can be used to predict whether the target wave conditions are met for a given physical model layout and wave forcing. The XBeach non-hydrostatic two-layer model is a computationally efficient numerical model that has been validated for spectral wave parameters, but lacks validation of the simulated wave height distributions. In this work, wave flume data with high spatial density over a sloping foreshore is used to validate the ability of this numerical model to reproduce both spectral wave parameters and wave height distributions. As part of this effort, optimal settings have been derived for the wave breaking formulation used in the numerical model, resulting in recommended values for the maxbrsteep and reformsteep parameters of 0.40 and 0.20 respectively. From the results of the validation it is concluded that the numerical model is unsuccessful in reproducing the validation tests with 5.0% wave steepness, potentially due to the higher kph numbers on the generating model boundary. Hence, using the numerical model with values of kph ≥ 2 on the model boundary is not recommended. The XBeach non-hydrostatic two-layer model performs much better for the 1.0% and 2.5% wave steepness tests, where the spectral wave parameters are represented well. The corresponding wave height distributions are represented reasonably well up to the point that the relative water depth gets very shallow. For shallower water, the model is expected to underestimate the higher waves in the wave height distribution. Additionally, the numerical model is shown to reproduce the wave height distribution better than a commonly used analytical formulation for wave height distributions on slopes.

Irradiated Atmospheres. I. Heating by Vertical-mixing-induced Energy Transport

Observations have revealed unique temperature profiles in hot Jupiter atmospheres. We propose that the energy transport by vertical mixing could lead to such thermal features. In our new scenario, strong absorbers, TiO, and VO are not necessary. Vertical mixing could be naturally excited by atmospheric circulation or internal gravity wave breaking. We perform radiative transfer calculations by taking into account the vertical-mixing-driven energy transport. The radiative equilibrium is replaced by the radiative-mixing equilibrium. We investigate how the mixing strength, K zz, affects the atmospheric temperature–pressure profile. Strong mixing can heat the lower atmosphere and cool the upper atmosphere. This effect has important effects on the atmosphere's thermal features that would form without mixing. In certain circumstances, it can induce temperature inversions in scenarios where the temperature monotonically increases with increasing pressure under conditions of lower thermal band opacity. Temperature inversions show up as K zz increases with altitude due to shear interaction with the convection layer. The atmospheric thermal structure of HD 209458b can be well fitted with K zz ∝ (P/1 bar)−1/2 cm2 s−1. Our findings suggest vertical mixing promotes temperature inversions and lowers K zz estimates compared to prior studies. Incorporating chemical species into vertical mixing will significantly affect the thermal profile due to their temperature sensitivity.

Analysis of Tidal Cycle Wave Breaking Distribution Characteristics on a Low-Tide Terrace Beach Using Video Imagery Segmentation

Wave breaking is a fundamental process in ocean energy dissipation and plays a crucial role in the exchange between ocean and nearshore sediments. Foam, the primary visible feature of wave breaking areas, serves as a direct indicator of wave breaking processes. Monitoring the distribution of foam via remote sensing can reveal the spatiotemporal patterns of nearshore wave breaking. Existing studies on wave breaking processes primarily focus on individual wave events or short timescales, limiting their effectiveness for nearshore regions where hydrodynamic processes are often represented at tidal cycles. In this study, video imagery from a typical low-tide terrace (LTT) beach was segmented into four categories, including the wave breaking foam, using the DeepLabv3+ architecture, a convolutional neural networks (CNNs)-based model suitable for semantic segmentation in complex visual scenes. After training and testing on a manually labelled dataset, which was divided into training, validation, and testing sets based on different time periods, the overall classification accuracy of the model was 96.4%, with an accuracy of 96.2% for detecting wave breaking foam. Subsequently, a heatmap of the wave breaking foam distribution over a tidal cycle on the LTT beach was generated. During the tidal cycle, the foam distribution density exhibited both alongshore variability, and a pronounced bimodal structure in the cross-shore direction. Analysis of morphodynamical data collected in the field indicated that the bimodal structure is primarily driven by tidal variations. The wave breaking process is a key factor in shaping the profile morphology of LTT beaches. High-frequency video monitoring further showed the wave breaking patterns vary significantly with tidal levels, leading to diverse geomorphological features at various cross-shore locations.