scholarly journals APPLICATION OF WAVE DIFFRACTION DATA

1968 ◽  
Vol 1 (11) ◽  
pp. 16 ◽  
Author(s):  
Richard Silvester ◽  
Teck-Kong Lim
Keyword(s):  
Experimental Data ◽  
Diffraction Data ◽  
Wave Diffraction ◽  
Wave Reflection ◽  
Incident Angle ◽  
Spreading Process ◽  
Simple Addition ◽  
Arc Distance ◽  
Diffraction Coefficient ◽  
Wave Heights

By considering separately the two terms of the Sommerfeld solution of wave diffraction behind a semi-infinite breakwater, the influence of the wave reflection from the structure can be evaluated The diffraction coefficient at any point can be obtained from a graph or table for full, partial or no reflection by the simple addition of two coefficients From the similarity of the energy-spreading process to the dam-burst problem, it was found that wave heights decreased consistently along the near circular crests for all distances from the breakwater tip For a workable range of incident angle and distance from the breakwater, wave heights could be defined by this arc distance from the shadow line expressed in wave lengths These relationships have been verified experimentally for all but the smallest incident angle in proximity to the breakwater This can be likened to the dam model in which the dam is moving too slowly to permit normal spreading. The several theoretical solutions for the breakwater gap, when graphed on the same basis, are shown to be very similar, diverging only for small incident angles New parameters are provided which greatly simplify the presentation of information The scatter of past experimental data precludes the verification of this theory and indicates the need for further tests.

scholarly journals The predictability of the "Voyager" accident

2008 ◽  
Vol 8 (3) ◽  
pp. 533-537 ◽  
Author(s):  
L. Bertotti ◽  
L. Cavaleri
Keyword(s):  
Experimental Data ◽  
Measured Data ◽  
Balearic Islands ◽  
Local Conditions ◽  
Best Estimate ◽  
Non Linear ◽  
Local Wave ◽  
Wave Heights ◽  
Wave Conditions

Abstract. On 14 February 2005 a severe mistral storm caused substantial damage to the passenger cruiser "Voyager" between Balearic Islands and Sardinia. The storm had been well predicted. However, the ship was hit by one or more, apparently unexpected, large waves. Our aim was to understand if this was a freak event or it was within the expectable probability. At this aim we use our best estimate of the local wave conditions, obtained combining modelling and measured data. Starting from these we derive the probability of large waves, considering both linear and non-linear cases. Notwithstanding a correction towards the worse of the, otherwise inconsistent, available reports, on the basis of the data at disposal we conclude that, given the local conditions, the event was within the range of the potentially expectable wave heights. This turns out to be even more the case on the basis of recent results based on theoretical and experimental data.

scholarly journals WAVE FORCES ON SQUARE CAISSONS

1976 ◽  
Vol 1 (15) ◽  
pp. 132 ◽  
Author(s):  
G.R. Mogridge ◽  
W.W. Jamieson
Keyword(s):  
Experimental Data ◽  
Theoretical Method ◽  
Wave Forces ◽  
Simple Method ◽  
Method Of Calculation ◽  
Wave Flume ◽  
Wide Range ◽  
Wave Heights ◽  
And Storage ◽  
Water Depths

The forces and overturning moments exerted by waves on large vertical square-section caissons have been measured in the laboratory. Each model caisson extended from the bottom of a wave flume through the water surface and was oriented either with one side perpendicular to the direction of wave propagation or turned through an angle of forty-five degrees to this position. For a given orientation, each model was tested for a range of wave heights (up to the point of breaking) for various wave periods and water depths. A digital computer was used for the acquisition, processing, plotting and storage of the experimental data. In addition to the experimental work, an approximate theoretical method is presented which allows the wave loadings on a square caisson to be estimated by means of a simple desk calculation. The experimental data shows that this simple method of calculation is reasonably accurate over a wide range of wave conditions and caisson sizes.

Frequency-dependent spherical-wave reflection coefficient inversion in acoustic media: Theory to practice

Geophysics ◽  
2020 ◽  
Vol 85 (4) ◽  
pp. R425-R435
Author(s):  
Binpeng Yan ◽  
Shangxu Wang ◽  
Yongzhen Ji ◽  
Xingguo Huang ◽  
Nuno V. da Silva
Keyword(s):  
Reflection Coefficient ◽  
Wave Reflection ◽  
Incident Angle ◽  
Spherical Wave ◽  
Frequency Dependent ◽  
Amplitude Variation With Offset ◽  
Reflection Data ◽  
Alternative Approach ◽  
Acoustic Media ◽  
The Time Domain

As an approximation of the spherical-wave reflection coefficient (SRC), the plane-wave reflection coefficient does not fully describe the reflection phenomenon of a seismic wave generated by a point source. The applications of SRC to improve analyses of seismic data have also been studied. However, most of the studies focus on the time-domain SRC and its benefit to using the long-offset information instead of the dependency of SRC on frequency. Consequently, we have investigated and accounted for the frequency-dependent spherical-wave reflection coefficient (FSRC) and analyzed the feasibility of this type of inversion. Our inversion strategy requires a single incident angle using reflection data for inverting the density and velocity ratios, which is distinctly different from conventional inversion methods using amplitude variation with offset. Hence, this investigation provides an alternative approach for estimating media properties in some contexts, especially when the range of aperture of the reflection angles is limited. We apply the FSRC theory to the inversion of noisy synthetic and field data using a heuristic algorithm. The multirealization results of the inversion strategy are consistent with the feasibility analysis and demonstrate the potential of the outlined method for practical application.

Composition-dependent magnitude of atomic shuffles in Ti–Nb martensites

2014 ◽  
Vol 47 (4) ◽  
pp. 1374-1379 ◽  
Author(s):  
Matthias Bönisch ◽  
Mariana Calin ◽  
Lars Giebeler ◽  
Arne Helth ◽  
Annett Gebert ◽  
...  
Keyword(s):  
Experimental Data ◽  
Chemical Composition ◽  
Diffraction Data ◽  
Structural Changes ◽  
Structural Characteristics ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Orthorhombic Unit Cell ◽  
Homogenization Treatment ◽  
X Ray

In this work the structural characteristics of martensitic phases in the Ti–Nb system are studied in detail. While the distortion of the orthorhombic unit cell of α′′-martensite by the addition of β-stabilizing atoms is well documented in the literature, comprehensive experimental data on the detailed atomic positions and how they vary with chemical composition are missing. For this study, a series of binary Ti–Nb alloys were prepared by casting techniques, followed by homogenization treatment and water quenching. Rietveld-based analyses of X-ray diffraction data were used to study the gradual structural changes of α′- and α′′-martensites effected by the addition of Nb, and their compositional boundaries were determined. In the case of orthorhombic α′′, it was established that, besides the lattice parameters, the positions of the atoms on the (002)α′′planes respond very sensitively to the amount of Nb present.

Modeling the sloshing problem in a rectangular tank with submerged incomplete baffles

2016 ◽  
Vol 26 (3/4) ◽  
pp. 722-744 ◽  
Author(s):  
Marcela A. Cruchaga ◽  
Carlos Ferrada ◽  
Nicolás Márquez ◽  
Sebastián Osses ◽  
Mario Storti ◽  
...  
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Wave Height ◽  
Numerical Study ◽  
Free Surface Flows ◽  
Numerical Results ◽  
Surface Evolution ◽  
Content Type ◽  
Near Resonance ◽  
Wave Heights

Purpose – The present work is an experimental and numerical study of a sloshing problem including baffle effects. The purpose of this paper is to assess the numerical behavior of a Lagrangian technique to track free surface flows by comparison with experiments, to report experimental data for sloshing at different conditions and to evaluate the effectiveness of baffles in limiting the wave height and the wave propagation. Design/methodology/approach – Finite element simulations performed with a fixed mesh technique able to describe the free surface evolution are contrasted with experimental data. The experiments consist of an acrylic tank of rectangular section designed to attach baffles of different sizes at different distance from the bottom. The tank is filled with water and mounted on a shake table able to move under controlled horizontal motion. The free surface evolution is measured with ultrasonic sensors. The numerical results computed for different sloshing conditions are compared with the experimental data. Findings – The reported numerical results are in general in good agreement with the experiments. In particular, wave heights and frequencies response satisfactorily compared with the experimental data for the several cases analyzed during steady state forced sloshing and free sloshing. The effectiveness of the baffles increases near resonance conditions. From the set of experiments studied, the major reduction of the wave height was obtained when larger baffles were positioned closer to the water level at rest. Practical implications – Model validation: evaluation of the effectiveness of non-massive immersed baffles during sloshing. Originality/value – The value of the present work encompass the numerical and experimental study of the effect of immersed baffles during sloshing under different imposed conditions and the comparison of numerical results with the experimental data. Also, the results shown in the present work are a contribution to the understanding of the role in the analysis of the proposed problem of some specific aspects of the geometry and the imposed motion.

High-Efficiency Solar Power Supply Design

2012 ◽  
Vol 605-607 ◽  
pp. 433-437
Author(s):  
Hong Yang ◽  
Wen Qi Huang ◽  
Zhen Fei Wang ◽  
Long Guang Chen ◽  
Yao Yin
Keyword(s):  
Experimental Data ◽  
Power Supply ◽  
High Efficiency ◽  
Incident Angle ◽  
Tracking System ◽  
Fresnel Lens ◽  
Solar Panels ◽  
Solar Module ◽  
Charging System ◽  
Voltage Current Characteristic

In order to improve the efficiency of solar module, we have designed the Fresnel lens concentrated system and charging system, their schematic diagrams are depicted detailed in this paper. The experimental data show that adding Fresnel lens parts can improve the solar panels' power from 130% to 200% and incident angle can affect solar panels' voltage current characteristic deeply. All of these results can give some support to design the tracking system.

scholarly journals Crystallographic raw data, education and refereeing

2016 ◽  
Vol 62 (3) ◽  
pp. 257-261
Author(s):  
John R. Helliwell
Keyword(s):  
Experimental Data ◽  
Protein Data Bank ◽  
Structural Biology ◽  
Diffraction Data ◽  
Review Process ◽  
Data Bank ◽  
The Impact ◽  
And Training ◽  
Scientific Achievements ◽  
Future Plans

This article provides an overview of the preservation of raw diffraction data, then addresses the impact on future plans in the education and training of our community with respect to raw diffraction data and its potential reuse, and, thirdly presents the issue of referee access to the underpinning diffraction data and coordinates, as well as the Protein Data Bank Validation Report, in the review process of structural biology articles submitted for publication. Overall I pay tribute to the scientific achievements of Alex Wlodawer, who is also an ardent advocate of the importance of experimental data

scholarly journals A Seven-Parameter BRDF Model with Double-Peak Characteristic Suitable for Sandy Soil

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Yu-Feng Yang ◽  
Wen-Shuai Li ◽  
Han-Zhi Zhang
Keyword(s):  
Experimental Data ◽  
Genetic Algorithm ◽  
Sandy Soil ◽  
Incident Angle ◽  
Mean Square ◽  
Double Peak ◽  
Practical Project ◽  
Parameter Values ◽  
Mean Square Errors ◽  
Combined Data

A seven-parameter BRDF model with double-peak characteristic was proposed in this paper, which can fit double-peak data. The global genetic algorithm was used to model the BRDF experimental data of sandy soil, and the parameter values and relative mean square error of the seven-parameter BRDF model were obtained. The results proved the correctness of the model, and the relative mean square errors of this model are, respectively, 0.30%, 0.22%, 0.26%, and 0.25% corresponding to the incident angles of 15°, 30°, 45°, and 60°. Additionally, we also combined data from four incident angles to derive seven parameters, which do not depend on incident angle, and the overall error is 1.79%. Finally, in order to intuitively show the BRDF of sandy soil, 3D BRDF graph of sandy soil with different incident angles is, respectively, given. It will be of great significance in practical project applications.

scholarly journals Internal Wave Generation in a Non-Hydrostatic Wave Model

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 986 ◽  
Author(s):  
Panagiotis Vasarmidis ◽  
Vasiliki Stratigaki ◽  
Tomohiro Suzuki ◽  
Marcel Zijlema ◽  
Peter Troch
Keyword(s):  
Experimental Data ◽  
Internal Wave ◽  
Wave Model ◽  
Wave Generation ◽  
Surface Elevation ◽  
Frequency Spectra ◽  
Directional Waves ◽  
Spatially Distributed ◽  
Wave Heights ◽  
Internal Wave Generation

In this work, internal wave generation techniques are developed in an open source non-hydrostatic wave model (Simulating WAves till SHore, SWASH) for accurate generation of regular and irregular long-crested waves. Two different internal wave generation techniques are examined: a source term addition method where additional surface elevation is added to the calculated surface elevation in a specific location in the domain and a spatially distributed source function where a spatially distributed mass is added in the continuity equation. These internal wave generation techniques in combination with numerical wave absorbing sponge layers are proposed as an alternative to the weakly reflective wave generation boundary to avoid re-reflections in case of dispersive and directional waves. The implemented techniques are validated against analytical solutions and experimental data including water surface elevations, orbital velocities, frequency spectra and wave heights. The numerical results show a very good agreement with the analytical solution and the experimental data indicating that SWASH with the addition of the proposed internal wave generation technique can be used to study coastal areas and wave energy converter (WEC) farms even under highly dispersive and directional waves without any spurious reflection from the wave generator.

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