scholarly journals Wave Peel Tracking: A New Approach for Assessing Surf Amenity and Analysis of Breaking Waves

2021 ◽  
Vol 13 (17) ◽  
pp. 3372
Author(s):  
Michael Thompson ◽  
Ivan Zelich ◽  
Evan Watterson ◽  
Tom E. Baldock
Keyword(s):  
Wave Breaking ◽  
Objective Assessment ◽  
Breaking Waves ◽  
Assessment Method ◽  
Coastal Development ◽  
Gold Coast ◽  
New Wave ◽  
New Approach ◽  
Automated Method ◽  
The Impact

The creation and protection of surfing breaks along populated coastlines have become a consideration for many councils and governments as surfing breaks are a major driver of tourism. To assess the surf amenity of surfing breaks, a quantitative and objective assessment method is required. A new wave peel tracking (WPT) method has been developed using a shore-based camera to assess surf amenity by measuring and quantifying potential surfing ride rate, length, duration, speed and direction on a wave-by-wave basis. The wave peel (or “curl” below the wave peak) is the optimal surfing region on a wave, and each wave peel track represents a surfable ride. Wave peel regions are identified, classified and tracked using traditional and machine learning-based computer vision techniques. The methodology is validated by comparing the rectified wave peel tracks with GPS-measured tracks from surfers in the wave peel regions. The WPT methodology is evaluated with data from a reef and adjacent natural beach at the Gold Coast, Australia. The reef produced longer ride lengths than the nearshore region and showed a consistent breaking location along the reef crest. Spatial maps of the wave peel tracks show the influence of tides on the wave breaking patterns and intensity. The WPT algorithm provides a robust, automated method for quantifying surf amenity to provide baseline data for surf break conservation. The methodology has potential uses to verify numerical modelling of surf breaks and to assess the impact of coastal development on surf breaks.

scholarly journals Observations of Breaking Waves and Energy Dissipation in Modulated Wave Groups

2018 ◽  
Vol 48 (12) ◽  
pp. 2937-2948 ◽  
Author(s):  
David W. Wang ◽  
Hemantha W. Wijesekera
Keyword(s):  
Energy Dissipation ◽  
Wave Height ◽  
Wave Breaking ◽  
Dissipation Rate ◽  
Breaking Waves ◽  
Wave Groups ◽  
Dissipation Rates ◽  
Local Wave ◽  
Tke Dissipation Rate ◽  
The Impact

AbstractIt has been recognized that modulated wave groups trigger wave breaking and generate energy dissipation events on the ocean surface. Quantitative examination of wave-breaking events and associated turbulent kinetic energy (TKE) dissipation rates within a modulated wave group in the open ocean is not a trivial task. To address this challenging topic, a set of laboratory experiments was carried out in an outdoor facility, the Oil and Hazardous Material Simulated Environment Test Tank (203 m long, 20 m wide, 3.5 m deep). TKE dissipation rates at multiple depths were estimated directly while moving the sensor platform at a speed of about 0.53 m s−1 toward incoming wave groups generated by the wave maker. The largest TKE dissipation rates and significant whitecaps were found at or near the center of wave groups where steepening waves approached the geometric limit of waves. The TKE dissipation rate was O(10−2) W kg−1 during wave breaking, which is two to three orders of magnitude larger than before and after wave breaking. The enhanced TKE dissipation rate was limited to a layer of half the wave height in depth. Observations indicate that the impact of wave breaking was not significant at depths deeper than one wave height from the surface. The TKE dissipation rate of breaking waves within wave groups can be parameterized by local wave phase speed with a proportionality breaking strength coefficient dependent on local steepness. The characterization of energy dissipation in wave groups from local wave properties will enable a better determination of near-surface TKE dissipation of breaking waves.

scholarly journals Using wavelet spectrum analysis to resolve breaking events in the wind wave time series

2004 ◽  
Vol 22 (10) ◽  
pp. 3335-3345 ◽  
Author(s):  
P. C. Liu ◽  
A. V. Babanin
Keyword(s):  
Time Series ◽  
Spectrum Analysis ◽  
Wave Breaking ◽  
Field Measurements ◽  
Finite Depth ◽  
Breaking Waves ◽  
Wavelet Spectrum ◽  
New Approach ◽  
Equivalent Wave

Abstract. This paper presents the development of a new approach, based on wavelet spectrum analysis, for the detection of breaking waves in a time series of surface wave fluctuations. The approach is shown to be capable of producing equivalent wave breaking statistics as field measurements based on detection of whitecaps at a fixed point of observation. This wavelet-based approach is applicable to both deep water and finite depth environments. Based on applications of this approach to the analysis of available field data, a novel classification of wave breaking processes that consists of incipient, developing, and subsiding phases is proposed.

scholarly journals 3D Particle Tracking Velocimetry applied to droplets generated by breaking waves

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Reyna Guadalupe RAMIREZ DE LA TORRE ◽  
Atle Jensen
Keyword(s):  
Particle Tracking ◽  
Wave Breaking ◽  
Particle Tracking Velocimetry ◽  
Wave Train ◽  
Vertical Wall ◽  
Breaking Waves ◽  
Initial Distribution ◽  
Polar Regions ◽  
Droplet Sizes ◽  
The Impact

One of the environmental difficulties of exploring the polar regions is marine icing. The understanding of this phenomenon is important for the safety of installations, ships and people that operates in these environments. One of the main sources of marine icing is wave breaking. Therefore, experimental and field work has been conducted to understand the break-up of waves in different situations and some explanation have been proposed to the instabilities that create the spray formation. In this work, two different situations of wave breaking were studied: 1. Solitary waves were created and steepened by the use of a beach. The waves impacted on a vertical wall with different wall heights. 2. Violent plunging breakers were created by a focusing wave train and a sloping beach. The main objective of these experiments was to quantify the production of droplets from the impact by using Particle Tracking Velocimetry in 3 dimensions. It was found that the initial distribution of droplet sizes is similar in both experiments. These distributions are compared with previous studies, where the distribution of droplet sizes in different experimental cases were approximated by lognormal, Weibull or G-distributions respectively.

Coming-of-Age Cinema in New Zealand

2017 ◽  
Author(s):  
Alistair Fox
Keyword(s):  
Coming Of Age ◽  
Belief Systems ◽  
Time Frame ◽  
New Wave ◽  
Art Cinema ◽  
Literary Sources ◽  
French New Wave ◽  
Significant Phenomenon ◽  
The Impact ◽  
New Zealanders

This book investigates the coming-of-age genre as a significant phenomenon in New Zealand’s national cinema, tracing its development from the 1970s to the present day. A preliminary chapter identifies the characteristics of the coming-of-age film as a genre, tracing its evolution and the influence of the French New Wave and European Art Cinema, and speculating on the role of the genre in the output of national cinemas. Through case studies of fifteen significant films, including The God Boy, Sleeping Dogs, The Scarecrow, Vigil, Mauri, An Angel at My Table, Heavenly Creatures, Once Were Warriors, Rain, Whale Rider, In My Father’s Den, 50 Ways of Saying Fabulous, Boy, Mahana, and Hunt for the Wilderpeople, subsequent chapters examine thematic preoccupations of filmmakers such as the impact of repressive belief systems and social codes, the experience of cultural dislocation, the expression of a Māori perspective through an indigenous “Fourth Cinema,” bicultural relationships, and issues of sexual identity, arguing that these films provide a unique insight into the cultural formation of New Zealanders. Given that the majority of films are adaptations of literary sources, the book also explores the dialogue each film conducts with the nation’s literature, showing how the time frame of each film is updated in a way that allows these films to be considered as a register of important cultural shifts that have occurred as New Zealanders have sought to discover their emerging national identity.

PHYSICAL INTERPRETATION OF WAVE BREAKING CRITERIA

2017 ◽  
Author(s):  
Sergey Kuznetsov ◽  
Sergey Kuznetsov ◽  
Yana Saprykina ◽  
Yana Saprykina ◽  
Boris Divinskiy ◽  
...  
Keyword(s):  
Nonlinear Wave ◽  
Wave Breaking ◽  
Second Harmonic ◽  
Vertical Axis ◽  
Breaking Waves ◽  
Wave Transformation ◽  
Spectral Structure ◽  
Similarity Parameter ◽  
Nonlinear Harmonics ◽  
The Waves

On the base of experimental data it was revealed that type of wave breaking depends on wave asymmetry against the vertical axis at wave breaking point. The asymmetry of waves is defined by spectral structure of waves: by the ratio between amplitudes of first and second nonlinear harmonics and by phase shift between them. The relative position of nonlinear harmonics is defined by a stage of nonlinear wave transformation and the direction of energy transfer between the first and second harmonics. The value of amplitude of the second nonlinear harmonic in comparing with first harmonic is significantly more in waves, breaking by spilling type, than in waves breaking by plunging type. The waves, breaking by plunging type, have the crest of second harmonic shifted forward to one of the first harmonic, so the waves have "saw-tooth" shape asymmetrical to vertical axis. In the waves, breaking by spilling type, the crests of harmonic coincides and these waves are symmetric against the vertical axis. It was found that limit height of breaking waves in empirical criteria depends on type of wave breaking, spectral peak period and a relation between wave energy of main and second nonlinear wave harmonics. It also depends on surf similarity parameter defining conditions of nonlinear wave transformations above inclined bottom.

Environmental Management of Coastal Development, State of Kuwait

1999 ◽  
Vol 40 (7) ◽  
pp. 47-53 ◽  
Author(s):  
Y. R. Marmoush
Keyword(s):  
Environmental Impact ◽  
Practical Experience ◽  
Term Effect ◽  
Marine Ecology ◽  
Coastal Development ◽  
Long Term Effect ◽  
Environmental Measures ◽  
Environmental Feasibility ◽  
Development State ◽  
The Impact

The impact of coastal development in Kuwait is to be assessed as per the following environmental conditions: water circulation, sediment behavior, water quality, and marine ecology and fisheries. The objectives of this assessment are to identify and predict the environmental impact associated with coastal development and the various activities involved in any coastal project. These activities and their associated impact can be grouped into two categories: those that occur during construction (short-term effect), and those that occur after construction (long-term effect). This paper attempts to present the fundamental issues related to the environmental measures and the practical experience required to evaluate the potential environmental impact of coastal development in Kuwait. The conclusions and general considerations regarding the environmental feasibility of coastal development are given, and measures to minimize the adverse impact on the environment are recommended.

scholarly journals Characteristics of Breaking Wave Forces on Piles over a Permeable Seabed

2021 ◽  
Vol 9 (5) ◽  
pp. 520
Author(s):  
Zhenyu Liu ◽  
Zhen Guo ◽  
Yuzhe Dou ◽  
Fanyu Zeng
Keyword(s):  
Wave Breaking ◽  
Stokes Equations ◽  
Slope Angle ◽  
Wave Force ◽  
Breaking Waves ◽  
Offshore Wind ◽  
Secondary Wave ◽  
Wave Forces ◽  
Breaking Wave ◽  
Breaking Wave Forces

Most offshore wind turbines are installed in shallow water and exposed to breaking waves. Previous numerical studies focusing on breaking wave forces generally ignored the seabed permeability. In this paper, a numerical model based on Volume-Averaged Reynolds Averaged Navier–Stokes equations (VARANS) is employed to reveal the process of a solitary wave interacting with a rigid pile over a permeable slope. Through applying the Forchheimer saturated drag equation, effects of seabed permeability on fluid motions are simulated. The reliability of the present model is verified by comparisons between experimentally obtained data and the numerical results. Further, 190 cases are simulated and the effects of different parameters on breaking wave forces on the pile are studied systematically. Results indicate that over a permeable seabed, the maximum breaking wave forces can occur not only when waves break just before the pile, but also when a “secondary wave wall” slams against the pile, after wave breaking. With the initial wave height increasing, breaking wave forces will increase, but the growth can decrease as the slope angle and permeability increase. For inclined piles around the wave breaking point, the maximum breaking wave force usually occurs with an inclination angle of α = −22.5° or 0°.

scholarly journals Efficiency Improvement of Miniaturized Heat Exchangers

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 25
Author(s):  
Iris Gerken ◽  
Thomas Wetzel ◽  
Jürgen J. Brandner
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Assessment Method ◽  
Flow Path ◽  
Transfer Enhancement ◽  
Pressure Losses ◽  
Pin Fin ◽  
Additional Pressure ◽  
The Impact

Micro heat exchangers have been revealed to be efficient devices for improved heat transfer due to short heat transfer distances and increased surface-to-volume ratios. Further augmentation of the heat transfer behaviour within microstructured devices can be achieved with heat transfer enhancement techniques, and more precisely for this study, with passive enhancement techniques. Pin fin geometries influence the flow path and, therefore, were chosen as the option for further improvement of the heat transfer performance. The augmentation of heat transfer with micro heat exchangers was performed with the consideration of an improved heat transfer behaviour, and with additional pressure losses due to the change of flow path (pin fin geometries). To capture the impact of the heat transfer, as well as the impact of additional pressure losses, an assessment method should be considered. The overall exergy loss method can be applied to micro heat exchangers, and serves as a simple assessment for characterization. Experimental investigations with micro heat exchanger structures were performed to evaluate the assessment method and its importance. The heat transfer enhancement was experimentally investigated with microstructured pin fin geometries to understand the impact on pressure loss behaviour with air.

scholarly journals SEM-PLS Approach to Green Building

Encyclopedia ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 472-481
Author(s):  
Nasim Aghili ◽  
Mehdi Amirkhani
Keyword(s):  
Structural Equation ◽  
Green Building ◽  
Well Being ◽  
The United States ◽  
Assessment Method ◽  
Assessment System ◽  
Renewable Materials ◽  
Sustainable Building ◽  
Building Operation ◽  
The Impact

Green buildings refer to buildings that decrease adverse environmental effects and maintain natural resources. They can diminish energy consumption, greenhouse gas emissions, the usage of non-renewable materials, water consumption, and waste generation while improving occupants’ health and well-being. As such, several rating tools and benchmarks have been developed worldwide to assess green building performance (GBP), including the Building Research Establishment Environmental Assessment Method (BREEAM) in the United Kingdom, German Sustainable Building Council (DGNB), Leadership in Energy and Environmental Design (LEED) in the United States and Canada, Comprehensive Assessment System for Built Environment Efficiency (CASBEE) in Japan, Green Star in Australia, Green Mark in Singapore, and Green Building Index in Malaysia. Energy management (EM) during building operation could also improve GBP. One of the best approaches to evaluating the impact of EM on GBP is by using structural equation modelling (SEM). SEM is a commanding statistical method to model testing. One of the most used SEM variance-based approaches is partial least squares (PLS), which can be implemented in the SmartPLS application. PLS-SEM uses path coefficients to determine the strength and significance of the hypothesised relationships between the latent constructs.

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