Wave Breaker Types on a Smooth and Impermeable 1:10 Slope

This research identified the types of wave breaker on a non-overtoppable, smooth and impermeable 1:10 slope under regular waves. Experimental tests were carried out in the Atmosphere-Ocean Interaction Flume of the Andalusian Institute for Earth System Research (University of Granada). Using the experimental space [log(h/L)–log(H/L)] and the alternate slope similarity parameter [χ = log (h/L H/L)], a complete set of breaker types was identified. Four types of wave breaker were then added to Galvin’s classification. Our results showed that the value of the Iribarren number was not sufficient to predict the expected type of wave breaker on the slope. Except for spilling and early plunging breakers, no biunivocal relationship was found between Ir and the type of breaker. The data obtained in the physical model were further enriched with the results of the flow characteristics and the wave energy transformation coefficients obtained with the IH-2VOF numerical model on a 1:10 impermeable slope. This research study, presented in this paper, showed that the Iribarren number is not a convenient wave breaking similarity parameter.

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BULK DISSIPATION AND FLOW CHARACTERISTICS IN CUBE ARMORED BREAKWATERS

Coastal Engineering Proceedings ◽

10.9753/icce.v36v.structures.40 ◽

2020 ◽

pp. 40

Author(s):

M. Victoria Moragues ◽

Maria Clavero ◽

Pilar Diaz-Carrasco ◽

Miguel A. Losada

Keyword(s):

Wave Energy ◽

Wave Breaking ◽

Flow Characteristics ◽

Main Function ◽

Key Factors ◽

Similarity Parameter ◽

Dissipation Term ◽

Porous Core ◽

Relative Water ◽

Run Up

The main function of a breakwater is dissipating wave energy. The breakwater dissipates energy by means of three mechanisms: (1) wave breaking over the slope; (2) wave propagation through the secondary layers and porous core; (3) interaction with the main armor layer. A revised dimensional analysis shows that relative water depth, h/L, and wave steepness, H/L, are key factors of breakwater performance. The product of (h/L) (HI/L) (hereinafter named as , alternate slope similarity parameter) can be applied to quantify the reflected and transmitted energy coefficients and the dissipation rate (Daz-Carrasco et al., 2020) and to identify the type of wave breaking and the domains of wave energy transformation (Moragues et al., 2020). The aim of this work is to analyze the dissipation term and its relation with the alternate slope similarity parameter , as well as correlate the flow characteristics (run-up, rundown) with the type of wave breaking and the bulk dissipation. For that purpose, former data (Clavero et al. 2020) and data from new tests have been analyzed. Whereas it is not clear that the use of different experimental techniques will give the same results in the laboratory, three different techniques for sea states selection have been taken into account in the new tests: (1) keeping constant h/L; (2) keeping constant H/L or Ir; and (3) varying h/L and H/L.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/oMZ05U0igCs

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PHYSICAL INTERPRETATION OF WAVE BREAKING CRITERIA

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.31519/conferencearticle_5b1b94019210f7.30842240 ◽

2017 ◽

Author(s):

Sergey Kuznetsov ◽

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.

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Investigation on the drag effect of a rolling element confined in the cavity of a cylindrical roller bearing

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/13506501211026063 ◽

2021 ◽

pp. 135065012110260

Author(s):

Wenjun Gao ◽

Shuo Zhang ◽

Xiaohang Li ◽

Zhenxia Liu

Keyword(s):

Open Space ◽

Roller Bearing ◽

Flow Characteristics ◽

Experimental Tests ◽

Windward Side ◽

Leeward Side ◽

Drag Effect ◽

Rolling Element ◽

Cylindrical Roller Bearing ◽

Cylindrical Roller

In cylindrical roller bearings, the drag effect may be induced by the rolling element translating in a fluid environment of the bearing cavity. In this article, the computational fluid dynamics method and experimental tests are employed to analyse its flow characteristics and pressure distribution. The results indicate that the pressure difference between the windward side and the leeward side of the cylinder is raised in view of it blocking the flow field. Four whirl vortexes are formed in four outlets of two wedge-shaped areas between the front part of the cylindrical surface and adjacent walls for the cylinder of L/ D = 1.5 at Re = 4.5 × 103. Vortex shedding is found in the direction of cylinder axis at Re = 4.5 × 104. The relationship between drag coefficient and Reynolds number is illustrated, obviously higher than that of the two-dimensional cylinder in open space.

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EXPERIMENTAL STUDY OF ENERGY DISSIPATION IN A SINGLE STEP CONDITION OVER A BROAD CRESTED WEIR

FUDMA Journal of Sciences ◽

10.33003/fjs-2021-0502-635 ◽

2021 ◽

Vol 5 (2) ◽

pp. 155-165

Author(s):

Bashir Tanimu ◽

Aliyu Bamaiyi Usman ◽

Al-Amin Danladi Bello ◽

Sulaiman Jamilu Abdullahi

Keyword(s):

Experimental Study ◽

Energy Dissipation ◽

Flow Rate ◽

Research Study ◽

Flow Characteristics ◽

Single Step ◽

Transition Flow ◽

Experimental Performance ◽

Empirical Relations ◽

Model Equations

This research study the experimental performance of broad-crested weir with single-step by introducing U/S and D/S round-nose and analysing the parameters that have effect on the shape of the step and their effects on the flow characteristics and energy dissipation (E%) downstream (D/S) of the weir. Furthermore, empirical relations for E% and flow rate due to the influencing factors were derived. The results showed that the weir model with = 1.000 gives a higher E% in comparison with other weir models. Flow regimes were observed i.e nappe flow for small discharges, transition flow for intermediate discharges and skimming flow for higher discharges. Two model equations were obtained, the first to dteremine the flow rate over the weir models and the second relation to estimate E% in terms of, and Froude number. The model () can be used in the design of prototype weirs in terms of energy dissipation

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Wave Induced Pressures on Pipelines Near a Sloping Boundary Due to Regular Waves

21st International Conference on Offshore Mechanics and Arctic Engineering, Volume 4 ◽

10.1115/omae2002-28147 ◽

2002 ◽

Author(s):

K. A. Roopsekhar ◽

V. Sundar

Keyword(s):

Time History ◽

Wave Direction ◽

Regular Waves ◽

Scattering Parameter ◽

Similarity Parameter ◽

Experimental Procedure ◽

Sloping Bed ◽

Model Setup ◽

Force Time ◽

Wave Induced

The hydrodynamic pressures due to regular waves around the circumference of a pipeline near a sloping rigid bed and placed parallel to the wave direction have been measured. The pressures were integrated to obtain the force time history, from which the peak horizontal and vertical forces were evaluated. The effects of relative clearance of pipe from the bed and its relative position from the toe of the sloping bed on the pressures and forces on the pipeline as a function scattering parameter and wave steepness are reported. The reflection characteristics of the sloping bed in the presence of the pipeline are reported as a function of surf similarity parameter and compared with the results from existing literature. The details of the model setup, experimental procedure, results and discussion are presented in this paper.

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Arnell, Prof. Nigel William, (born 10 Dec. 1959), Professor of Climate Systems Science, and Director, Walker Institute for Climate System Research, University of Reading, since 2007

10.1093/ww/9780199540884.013.u247110 ◽

2008 ◽

Keyword(s):

Research University ◽

Climate System ◽

Systems Science ◽

System Research ◽

Climate Systems

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The application of the KdV type equation in engineering simulation

Maejo International Journal of Energy and Environmental Communication ◽

10.54279/mijeec.v3i2.245174 ◽

2021 ◽

Vol 3 (2) ◽

pp. 7-10

Author(s):

Wael Sulayman Miftah Ammar ◽

Ying Shi

Keyword(s):

Wave Breaking ◽

Vries Equation ◽

Final Height ◽

Type Equation ◽

Experimental Tests ◽

Propagation Length ◽

Systematic Analysis ◽

Complete Disintegration ◽

Nonlinear Fourier Transform ◽

Discrete Solitons

Bores propagating in shallow water transform into undular bores and, finally, into trains of solitons. The observed number and height of these undulations and later discrete solitons are strongly dependent on the propagation length of the bore. Empirical results show that the final height of the leading soliton in the far-field is twice the initial mean bore height. The complete disintegration of the initial bore into a train of solitons requires very long propagation, but unfortunately, these required distances are usually not available in experimental tests of nature. Therefore, the analysis of the bore decomposition for experimental data into solitons is complicated and requires different approaches. Previous studies have shown that by applying the nonlinear Fourier transform based on the Ko- rteweg–de Vries equation (KdV-NFT) to bores and long-period waves propagating in constant depth, the number and height of all solitons can be reliably predicted already based on the initial bore-shaped free surface. Against this background, this study presents the systematic analysis of the leading-soliton amplitudes for non-breaking and breaking bores with different strengths in different water depths to validate the KdV-NFT results for non-breaking bores to show the limitations of wave breaking on the spectral results. The analytical results are compared with data from experimental tests, numerical simulations and other approaches from the literature.

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Proposal guidelines to implement the concepts of industry 4.0 into information technology companies

The TQM Journal ◽

10.1108/tqm-10-2019-0249 ◽

2020 ◽

Vol 32 (4) ◽

pp. 741-759

Author(s):

Tairine Pravadelli Cunha ◽

Mirian Picinini Méxas ◽

André Cantareli da Silva ◽

Osvaldo Luiz Gonçalves Quelhas

Keyword(s):

Information Technology ◽

Industry 4.0 ◽

Research University ◽

Industrial Revolution ◽

Research Study ◽

New Technologies ◽

Field Research ◽

Inductive Method ◽

Content Type ◽

Bibliographic Search

PurposeThe goal of this work is to propose guidelines for the Information Technology (IT) companies in Brazil to implement the concepts of Industry 4.0.Design/methodology/approachThis research study used inductive method, exploratory and descriptive research, and a bibliographic search was performed, besides using a qualitative research as field research. The IT professionals of companies in Brazil were used as the research university.FindingsWith the advances of technology and the advents of industrial revolutions, the profile of professionals and the relationship between employees and companies have been altered, fact that was demonstrated in the field research, making it possible to highlight: the knowledge degree of managers about the theme, it means, the perception of what Industry 4.0 is; how the organizations have already been adjusting to the new industrial revolution; the main challenges for this adjustment; the relevance for clients and opponents; among other discoveries. Therefore, companies must adapt to the new market demands, by improving their processes, investing in new technologies and training their employees.Practical implicationsActions for implementing Industry 4.0 in IT companies were proposed, such as understanding its organization, defining in which area of the business model the organization intends to make/have changes, discovering tendencies and developments that will have influence over the organization when applying the concepts of Industry 4.0, overcoming the major challenges and adhering to new technologies.Originality/valueWith the contribution toward the organization, it is expected that this study can fulfill the demands of clients and provide cost, personnel and time savings the best way possible. For the academy, the contribution lies in presenting a research study with a new theme and with focus on IT.

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Fluid-sediment dynamics around a barb: an experimental case study of a hydraulic structure for the Pacific Northwest

Canadian Journal of Civil Engineering ◽

10.1139/l05-033 ◽

2005 ◽

Vol 32 (5) ◽

pp. 853-867 ◽

Cited By ~ 15

Author(s):

James F Fox ◽

Athanasios N Papanicolaou ◽

Brandon Hobbs ◽

Casey Kramer ◽

Lisa Kjos

Keyword(s):

Pacific Northwest ◽

Large Scale ◽

Hydraulic Structure ◽

Flow Characteristics ◽

Experimental Tests ◽

Flow Regimes ◽

The Pacific ◽

Bank Protection ◽

Bank Stabilization ◽

First Time

Three sets of experimental tests are administered in the vicinity of a model barb — a unique hydraulic structure used to provide bank protection for mild-sloped, gravel-bed streams in the Pacific Northwest — under modeled, bankfull conditions. First, experiments are performed using acoustic Doppler velocimetry to provide a description of the flow characteristics around the model barb, as this is the first time that this type of structure has been considered. These initial experiments provide quantitative flow regimes as a guide for scour and spacing tests. Second, scour around the structure is described because existing knowledge in the literature is limited to scour in sand bed streams. Lastly, the performance of the barbs as it relates to bank protection is evaluated using the large-scale particle-image velocimeter for the first time to the authors' knowledge. The results provide quantification of three distinct flow regimes around a barb, scour geometry, and dimensionless ratios for scour depth and spacing for the barbs when designed for bankfull discharge in the Pacific Northwest.Key words: streambank erosion, bank stabilization, barb, flow diversion, hydraulic structure, turbulent eddies.

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