Acoustic Study of Wave-Breaking to Enhance the Understanding of Wave Physics

2020 ◽  
Author(s):  
Michael Odzer ◽  
Kristina Francke
Keyword(s):  
Wave Breaking ◽  
Ocean Waves ◽  
Breaking Waves ◽  
Video Data ◽  
Wave Tank ◽  
Potential Applications ◽  
Audio Data ◽  
Video And Audio ◽  
Bubble Sizes ◽  
Laboratory Tank

Abstract The sound of waves breaking on shore, or against an obstruction or jetty, is an immediately recognizable sound pattern which could potentially be employed by a sensor system to identify obstructions. If frequency patterns produced by breaking waves can be reproduced and mapped in a laboratory setting, a foundational understanding of the physics behind this process could be established, which could then be employed in sensor development for navigation. This study explores whether wave-breaking frequencies correlate with the physics behind the collapsing of the wave, and whether frequencies of breaking waves recorded in a laboratory tank will follow the same pattern as frequencies produced by ocean waves breaking on a beach. An artificial “beach” was engineered to replicate breaking waves inside a laboratory wave tank. Video and audio recordings of waves breaking in the tank were obtained, and audio of ocean waves breaking on the shoreline was recorded. The audio data was analysed in frequency charts. The video data was evaluated to correlate bubble sizes to frequencies produced by the waves. The results supported the hypothesis that frequencies produced by breaking waves in the wave tank followed the same pattern as those produced by ocean waves. Analysis utilizing a solution to the Rayleigh-Plesset equation showed that the bubble sizes produced by breaking waves were inversely related to the pattern of frequencies. This pattern can be reproduced in a controlled laboratory environment and extrapolated for use in developing navigational sensors for potential applications in marine navigation such as for use with autonomous ocean vehicles.

scholarly journals LABORATORY EXPERIMENTS ON THE INFLUENCE OF WIND ON NEARSHORE WAVE BREAKING

1988 ◽  
Vol 1 (21) ◽  
pp. 46
Author(s):  
Scott L. Douglass ◽  
J. Richard Weggel
Keyword(s):  
Wind Direction ◽  
Wave Breaking ◽  
Laboratory Experiments ◽  
Surf Zone ◽  
Breaking Waves ◽  
Wave Tank ◽  
Zone Width

The influence of wind on nearshore breaking waves was investigated in a laboratory wave tank. Breaker location, geometry, and type depended upon the wind acting on the wave as it broke. Onshore winds tended to cause waves to break earlier, in deeper water, and to spill: offshore winds tended to cause waves to break later, in shallower water, and to plunge. A change in wind direction from offshore to onshore increased the surf zone width by up to 100%. Wind's effect was greatest for waves which were near the transition between breaker types in the absence of wind. For onshore winds, it was observed that microscale breaking can initiate spilling breaking by providing a perturbation on the crest of the underlying wave as it shoals.

scholarly journals A Deep Learning Enhanced Novel Software Tool for Laryngeal Dynamics Analysis

2021 ◽  
pp. 1-15
Author(s):  
Andreas M. Kist ◽  
Pablo Gómez ◽  
Denis Dubrovskiy ◽  
Patrick Schlegel ◽  
Melda Kunduk ◽  
...  
Keyword(s):  
Neural Networks ◽  
Quantitative Analysis ◽  
High Speed ◽  
Voice Disorders ◽  
Vocal Folds ◽  
Video Data ◽  
Audio Data ◽  
Fully Automatic ◽  
Video And Audio

Purpose High-speed videoendoscopy (HSV) is an emerging, but barely used, endoscopy technique in the clinic to assess and diagnose voice disorders because of the lack of dedicated software to analyze the data. HSV allows to quantify the vocal fold oscillations by segmenting the glottal area. This challenging task has been tackled by various studies; however, the proposed approaches are mostly limited and not suitable for daily clinical routine. Method We developed a user-friendly software in C# that allows the editing, motion correction, segmentation, and quantitative analysis of HSV data. We further provide pretrained deep neural networks for fully automatic glottis segmentation. Results We freely provide our software Glottis Analysis Tools (GAT). Using GAT, we provide a general threshold-based region growing platform that enables the user to analyze data from various sources, such as in vivo recordings, ex vivo recordings, and high-speed footage of artificial vocal folds. Additionally, especially for in vivo recordings, we provide three robust neural networks at various speed and quality settings to allow a fully automatic glottis segmentation needed for application by untrained personnel. GAT further evaluates video and audio data in parallel and is able to extract various features from the video data, among others the glottal area waveform, that is, the changing glottal area over time. In total, GAT provides 79 unique quantitative analysis parameters for video- and audio-based signals. Many of these parameters have already been shown to reflect voice disorders, highlighting the clinical importance and usefulness of the GAT software. Conclusion GAT is a unique tool to process HSV and audio data to determine quantitative, clinically relevant parameters for research, diagnosis, and treatment of laryngeal disorders. Supplemental Material https://doi.org/10.23641/asha.14575533

scholarly journals Inhabiting spatial video and audio data: Towards a scenographic turn in the analysis of social interaction

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Paul McIlvenny
Keyword(s):  
Social Interaction ◽  
Video Data ◽  
Video Clips ◽  
Screen Capture ◽  
Audio Recordings ◽  
Actual Use ◽  
Video Data Collection ◽  
Audio Data ◽  
Video And Audio ◽  
Spatial Video

Consumer versions of the passive 360° and stereoscopic omni-directional camera have recently come to market, generating new possibilities for qualitative video data collection. This paper discusses some of the methodological issues raised by collecting, manipulating and analysing complex video data recorded with 360° cameras and ambisonic microphones. It also reports on the development of a simple, yet powerful prototype to support focused engagement with such 360° recordings of a scene. The paper proposes that we ‘inhabit’ video through a tangible interface in virtual reality (VR) in order to explore complex spatial video and audio recordings of a single scene in which social interaction took place. The prototype is a software package called AVA360VR (‘Annotate, Visualise, Analyse 360° video in VR’). The paper is illustrated through a number of video clips, including a composite video of raw and semi-processed multi-cam recordings, a 360° video with spatial audio, a video comprising a sequence of static 360° screenshots of the AVA360VR interface, and a video comprising several screen capture clips of actual use of the tool. The paper discusses the prototype’s development and its analytical possibilities when inhabiting spatial video and audio footage as a complementary mode of re-presenting, engaging with, sharing and collaborating on interactional video data.

Observations of Surface Waves and Wave Breaking: A Tribute to Nick Newman

2008 ◽  
Author(s):  
W. Kendall Melville ◽  
Lenonel Romero ◽  
Jessica Kleiss
Keyword(s):  
Surface Waves ◽  
Wave Breaking ◽  
Surface Displacement ◽  
Breaking Waves ◽  
Video Data ◽  
Physical Models ◽  
Lead Author ◽  
Strong Wind ◽  
Spectral Models ◽  
Gulf Of Tehuantepec

The Gulf of Tehuantepec is well known for having strong offshore winds, which occur predominantly during the winter months when significant atmospheric pressure differences develop between the Gulf of Mexico and the Pacific Ocean, forcing winds through a mountain gap at the head of the gulf. During the Gulf of Tehuantepec Experiment (GOTEX), conducted in February 2004, we collected surface-wave and wave-breaking measurements using a conical scanning lidar (NASA Airborne Terrain Mapper, ATM) and a downward-looking video camera on the NSF/NCAR C-130 aircraft. We present ATM observations of surface waves as well as statistical and spectral descriptions of the wave field. We also present measurements of the occurrence and strength of breaking using digital video data to identify actively breaking waves. In order to infer the dynamics of breaking from simple physical models, the kinematics of the breaking must be separated from the kinematics of the underlying waves. This is done using linear and nonlinear estimates of the underlying orbital velocities from the spatio-temporal surface displacement data measured by the ATM. Nonlinear estimation of the orbital velocities is described in a companion paper in this symposium (Grue et al., OMAE 2008). Frequent breaking is observed under the strong wind forcing. Examples of the spatial structure of waves are compared to simultaneous video imagery, giving an indication of the scale at which wave breaking occurs. The GOTEX observations, to almost full wave development, are tested against the latest wind-wave numerical spectral models that include the effects of wave generation, nonlinear wave-wave interactions and wave dissipation due to breaking. This paper is dedicated to Nick Newman by the lead author in appreciation of Nicks encouragement and assistance when he (WKM) moved to MIT in the early 1980s.

scholarly journals Semiempirical Dissipation Source Functions for Ocean Waves. Part I: Definition, Calibration, and Validation

2010 ◽  
Vol 40 (9) ◽  
pp. 1917-1941 ◽  
Author(s):  
Fabrice Ardhuin ◽  
Erick Rogers ◽  
Alexander V. Babanin ◽  
Jean-François Filipot ◽  
Rudy Magne ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wave Height ◽  
Wave Breaking ◽  
Wave Spectrum ◽  
Remote Sensing Data ◽  
Ocean Waves ◽  
Breaking Waves ◽  
Global Ocean ◽  
Short Waves ◽  
Wide Range

Abstract New parameterizations for the spectral dissipation of wind-generated waves are proposed. The rates of dissipation have no predetermined spectral shapes and are functions of the wave spectrum and wind speed and direction, in a way consistent with observations of wave breaking and swell dissipation properties. Namely, the swell dissipation is nonlinear and proportional to the swell steepness, and dissipation due to wave breaking is nonzero only when a nondimensional spectrum exceeds the threshold at which waves are observed to start breaking. An additional source of short-wave dissipation is introduced to represent the dissipation of short waves due to longer breaking waves. A reduction of the wind-wave generation of short waves is meant to account for the momentum flux absorbed by longer waves. These parameterizations are combined and calibrated with the discrete interaction approximation for the nonlinear interactions. Parameters are adjusted to reproduce observed shapes of directional wave spectra, and the variability of spectral moments with wind speed and wave height. The wave energy balance is verified in a wide range of conditions and scales, from the global ocean to coastal settings. Wave height, peak and mean periods, and spectral data are validated using in situ and remote sensing data. Some systematic defects are still present, but, overall, the parameterizations probably yield the most accurate estimates of wave parameters to date. Perspectives for further improvement are also given.

TOPOLOGICAL MAPPINGS OF VIDEO AND AUDIO DATA

2008 ◽  
Vol 18 (06) ◽  
pp. 481-489 ◽  
Author(s):  
COLIN FYFE ◽  
WESAM BARBAKH ◽  
WEI CHUAN OOI ◽  
HANSEOK KO
Keyword(s):  
Mean Squared Error ◽  
Video Data ◽  
Self Organizing Map ◽  
Generative Topographic Mapping ◽  
Data Set ◽  
Squared Error ◽  
Nonlinear Projection ◽  
Audio Data ◽  
Video And Audio ◽  
Self Organizing

We review a new form of self-organizing map which is based on a nonlinear projection of latent points into data space, identical to that performed in the Generative Topographic Mapping (GTM).1 But whereas the GTM is an extension of a mixture of experts, this model is an extension of a product of experts.2 We show visualisation and clustering results on a data set composed of video data of lips uttering 5 Korean vowels. Finally we note that we may dispense with the probabilistic underpinnings of the product of experts and derive the same algorithm as a minimisation of mean squared error between the prototypes and the data. This leads us to suggest a new algorithm which incorporates local and global information in the clustering. Both ot the new algorithms achieve better results than the standard Self-Organizing Map.

scholarly journals Remote Sensing Observations of Dominant Breaking Waves in Intermediate to Deep Water from a Lighthouse During Storm Conditions

2021 ◽  
Author(s):  
Caio Eadi Stringari ◽  
Jean-François Filipot ◽  
Fabien Leckler ◽  
Rui Duarte
Keyword(s):  
Remote Sensing ◽  
Deep Water ◽  
Wave Breaking ◽  
Rogue Waves ◽  
Breaking Waves ◽  
Offshore Structures ◽  
Video Data ◽  
Occurrence Rate ◽  
Winter Storms ◽  
Technical Issues

Wave breaking is one of the most important yet poorly understood water wave phenomena. It is via wave breaking that waves dissipate most of their energy and the occurrence of wave breaking directly influences several environmental processes, from ocean-atmosphere gas exchanges to beach morphodynamics. Large breaking waves also represent a major threat for navigation and for the survivability of offshore structures. This paper provides a systematic search for intermediate to deep water breaking waves with particular focus on the elusive occurrence of plunging breakers. Using modern remote sensing and deep learning techniques, we identify and track the evolution of over four thousand unique wave breaking events using video data collected from La Jument lighthouse during ten North Atlantic winter storms. Out of all identified breaking waves (Nb=4683), ≈22% were dominant breaking waves, that is, waves that have speeds within [0.77cp, 1.43cp], where cp is the peak wave speed. Correlations between the occurrence rate of dominant breaking waves (that is, waves per area and time per peak wave period) and wave steepness and wave age were observed. As expected, the number of identified plunging waves was small and six waves of all detected breaking waves, or 0.13%, could undoubtedly be considered as plunging waves. Two waves were also identified as unusually large, or rogue waves. Although afflicted by several technical issues, the data presented here provides a good indication that the probability of occurrence of plunging waves should be better incorporated into the design of offshore structures, particularly the ones that aim to harvest energy in offshore environments.

scholarly journals Convolutional Networks Used to Classify Video and Audio Data

2019 ◽  
Vol 27 (45) ◽  
pp. 113-120
Author(s):  
Marcel Nikmon ◽  
Roman Budjač ◽  
Daniel Kuchár ◽  
Peter Schreiber ◽  
Dagmar Janáčová
Keyword(s):  
Machine Learning ◽  
Deep Learning ◽  
Data Classification ◽  
Current Data ◽  
Video Data ◽  
Batch Size ◽  
Network Architectures ◽  
Convolutional Networks ◽  
Audio Data ◽  
Video And Audio

Abstract Deep learning is a kind of machine learning, and machine learning is a kind of artificial intelligence. Machine learning depicts groups of various technologies, and deep learning is one of them. The use of deep learning is an integral part of the current data classification practice in today’s world. This paper introduces the possibilities of classification using convolutional networks. Experiments focused on audio and video data show different approaches to data classification. Most experiments use the well-known pre-trained AlexNet network with various pre-processing types of input data. However, there are also comparisons of other neural network architectures, and we also show the results of training on small and larger datasets. The paper comprises description of eight different kinds of experiments. Several training sessions were conducted in each experiment with different aspects that were monitored. The focus was put on the effect of batch size on the accuracy of deep learning, including many other parameters that affect deep learning [1].

EFFECTS OF AN OIL SLICK ON WIND WAVES1

1979 ◽  
Vol 1979 (1) ◽  
pp. 665-674 ◽  
Author(s):  
Hsien-Ta Liu ◽  
Jung-Tai Lin
Keyword(s):  
Wave Breaking ◽  
Wind Wave ◽  
Wind Waves ◽  
Ocean Waves ◽  
Diesel Oil ◽  
Wave Tank ◽  
Oil Slick ◽  
Wave Profiles ◽  
The Waves ◽  
Integrated Program

ABSTRACT Laboratory experiments were performed to investigate the effects of an oil slick on ocean waves. This is part of an integrated program aimed at understanding the vertical dispersion of oil in the upper ocean. The experiments were conducted in a wind-wave tank which measured 9.1 m long, 1.2 m wide, and 1.8 m deep. Both wind waves and mechanically-generated waves with wind were considered. No. 2 Diesel oil was fed at a rate of 0.35 liters/sec onto the water surface from the upstream end of the wave tank. To measure the wave profiles, an optical sensor-photodiode wave gauge was developed and is described herein. The effects of an oil slick on wind waves were examined in terms of wave profiles and rms wave amplitudes. For wind waves, the presence of the oil slick damps the waves significantly. The amount of damping increases with the wind speed in the range from U∞ = 4 m/sec to 10 m/sec. At U∞ = 10 m/sec, the oil slick breaks into small lenses. The rms amplitudes of the wind-generated waves increase with the fetch without the oil slick, but they do not change appreciably in the presence of the oil slick. For mechanically-generated waves with wind, wave damping by the oil slick becomes insignificant when the waves are sufficiently steep and wave breaking occurs. Prior to wave breaking, however, steepening of the wave crests due to the presence of the oil slick has been observed occasionally as a result of the reduction in the surface tension by the oil film.

scholarly journals Calculation of the Accelerated Breaking-Roller Propagation Speed and Wave Energy Transfer to the Roller

2011 ◽  
Author(s):  
Takashi Okamoto ◽  
Conceic¸a˜o Juana Fortes
Keyword(s):  
Energy Transfer ◽  
Wave Breaking ◽  
Wave Motion ◽  
Propagation Speed ◽  
Breaking Waves ◽  
Energy Calculation ◽  
Energy Transfer Rate ◽  
Wave Tank ◽  
Slow Decay ◽  
Wave Celerity

Wave breaking has different physics from the potential flow wave motion. The roller model introduced by Svendsen [1] illustrates the separation of the wave motion and the roller. The roller propagation speed, therefore, is a very important factor for the energy calculation of the bore. The wave celerity data collected at the wave tank displays that the maximum roller propagation speed occurs when the wave has already decayed due to the breaking. This fact clearly displays that the bore energy cannot be calculated only from the wave height as it is done for non-breaking waves. It is certain that most the energy is dissipated through the roller formation in the outer surfzone, but a certain amount of energy is transferred to the roller at the same time and it accelerates the bore speed. Slow decay of the roller propagation speed indicates that the excess energy left in the roller dissipates in the inner surfzone at much slower rate than in the outer surfzone. Therefore, these two zones have to be clearly separated, but the amount of energy transferred into the roller is unknown. In this paper, we focus on the examination of the peak roller propagation speed that appears at the border of the outer and the inner surfzone by using the experimental data collected at the wave tank. In that way, the initial condition of roller propagation speed can be determined for the inner surfzone. The energy conservation between the wave motion and the roller kinetic energy derives an equation to calculate the roller propagation speed. The energy transfer rate is estimated by adjusting the value given by the full energy conversion with the observed roller propagation speed. It is found that about half of the energy is transferred into the roller. The model successfully illustrates the peak bore propagation speed which existing formulae cannot explain.

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