REFRACTIONOF WIND WAVES IN MESHWATER ZONNE BY THE SHORES OF ANY UNDERWATER SLOPE MORFOSTRUCTURE

2018 ◽  
Author(s):  
А. Марченко ◽  
A. Marchenko ◽  
И. Никитин ◽  
I. Nikitin
Keyword(s):  
Wave Field ◽  
Coastal Zone ◽  
Coastal Water ◽  
Wind Waves ◽  
Numerical Results ◽  
Theoretical Studies ◽  
Wave Tank ◽  
Analytical Technique ◽  
Underwater Slope ◽  
The Given

The graphical analytical technique for refraction waves in coastal water areas under condition of water slope relief in shapes of bathymetry charts. The given technique is based on results of theoretical studies in water areas refractions in sea bays made by the authoress. The convergences data obtained are suited for foolproof calculations results for proposed methods of wave tank supervision along with natural of measurements and numerical results. The given technique make it possible to recreate the approximate picture wave field refraction on the coastal zone up to the border of waves turnover.

scholarly journals PROBLEMS OF SEDIMENTS TRANSPORT MODELING IN THE COASTAL AREA

2021 ◽  
Vol 49 (1) ◽  
pp. 93-141
Author(s):  
R. D. Kosyan ◽  
B. V. Divinsky
Keyword(s):  
Sediment Transport ◽  
Surface Waves ◽  
Wave Field ◽  
Frequency Distribution ◽  
Coastal Zone ◽  
Bottom Sediments ◽  
Wave Energy ◽  
Laboratory Experiments ◽  
Wind Waves ◽  
Wave Spectrum

Due to the development of measuring instruments, a more detailed analysis of the wave field and the field of suspended sediments spatio-temporal characteristics has become possible. Through the efforts of Russian specialists over the past decades: A unique database of observations of the sediment movement in storm situations in different physical and geographical areas of the coastal zone of the Black, Baltic, North, Mediterranean, South China Seas has been collected, supplemented by extensive data of laboratory experiments in the best laboratory in Europe (Hannover, Germany). New experimental material has been obtained to determine the physical features of sediment transport by wave flow. The main mechanisms controlling the amplitude and phase relationships of the concentration fluctuations and discharge of suspended sediment on time scales less than the period of the peak of the wind wave spectrum are considered. The presence of low-frequency fluctuations in sediment concentration with a period of the order of several periods of wind waves and an amplitude several times higher than the average value of concentration is noted. The previously unexplored problem of the wave energy frequency distribution in the spectrum of surface waves influence on the sediment transport has been analyzed. Differences in the response of the washed-out bottom to an external disturbance, represented by irregular surface waves with constant integral characteristics (significant wave height and period of the spectrum peak) and variable wave energy frequency distribution, were revealed. The influence of swell waves on the redistribution of bottom sediments in the sea coastal zone was investigated. It is shown that dividing the wave field into separate components allows a more correct description of the spatiotemporal structure of surface waves, as well as a significant refinement of the bottom sediment transport schemes in the coastal zone. Using the example of the Anapa bay bar, it is shown that situations are possible in which the alongshore flow of bottom sediments is almost completely determined by swell waves. The results of field and laboratory experiments make it possible to determine the directions for further research on the creation of physically based models of sediment transport by waves and wave currents.

scholarly journals A novel method for the analytical solution of fractional Zakharov–Kuznetsov equations

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Rasool Shah ◽  
Hassan Khan ◽  
Dumitru Baleanu ◽  
Poom Kumam ◽  
Muhammad Arif
Keyword(s):  
Present Method ◽  
Decomposition Method ◽  
Fractional Derivatives ◽  
Adomian Decomposition Method ◽  
Current Method ◽  
Analytical Technique ◽  
Suggested Technique ◽  
Adomian Decomposition ◽  
Novel Method ◽  
The Given

AbstractIn this article, an efficient analytical technique, called Laplace–Adomian decomposition method, is used to obtain the solution of fractional Zakharov– Kuznetsov equations. The fractional derivatives are described in terms of Caputo sense. The solution of the suggested technique is represented in a series form of Adomian components, which is convergent to the exact solution of the given problems. Furthermore, the results of the present method have shown close relations with the exact approaches of the investigated problems. Illustrative examples are discussed, showing the validity of the current method. The attractive and straightforward procedure of the present method suggests that this method can easily be extended for the solutions of other nonlinear fractional-order partial differential equations.

scholarly journals Optimization of a k-covering of a bounded set with circles of two given radii

2021 ◽  
Vol 11 (1) ◽  
pp. 232-240
Author(s):  
Alexander V. Khorkov ◽  
Shamil I. Galiev
Keyword(s):  
Linear Programming ◽  
Numerical Method ◽  
Lower Bounds ◽  
Integer Linear Programming ◽  
Numerical Results ◽  
Programming Models ◽  
Bounded Set ◽  
The Given

Abstract A numerical method for investigating k-coverings of a convex bounded set with circles of two given radii is proposed. Cases with constraints on the distances between the covering circle centers are considered. An algorithm for finding an approximate number of such circles and the arrangement of their centers is described. For certain specific cases, approximate lower bounds of the density of the k-covering of the given domain are found. We use either 0–1 linear programming or general integer linear programming models. Numerical results demonstrating the effectiveness of the proposed methods are presented.

Hydrodynamic Сonditions of the Bakalskaya Spit Degradation (Western Crimea) over the Past 30 Years

2021 ◽  
Vol 37 (3) ◽  
Author(s):  
B. V. Divinsky ◽  
R. D. Kosyan ◽  
◽  
Keyword(s):  
Discriminant Analysis ◽  
Coastal Zone ◽  
Satellite Images ◽  
Wind Waves ◽  
Total Duration ◽  
Wave Model ◽  
Statistical Characteristics ◽  
Wave Impact ◽  
Annual Variability ◽  
The Impact

Purpose. The paper is aimed at studying the morphodynamic features of the Bakalskaya Spit evolution being influenced by the sea wind waves and swell, namely assessment of inter-annual variations in the alluvial (erosion) areas of the Bakalskaya Spit coastline, analysis of inter-annual variability of the wind wave parameters, determination of the surface wave characteristics (or a combination of a few ones) responsible for the processes of the bottom material erosion or accumulation in the coastal zone. Methods and Results. Based on the analysis of satellite images for 1984–2016, the areas of the bottom material accumulation or erosion of the Bakalskaya Spit coastline were determined. Application of the spectral wave model permitted to obtain time series of the main parameters of wind waves and swell (significant wave heights and propagation directions) in the Bakalskaya Spit coastal zone with the 1 hr time resolution for the period from 1984 to 2016. The characteristics of surface waves responsible for the coastline deformation were revealed using the discriminant analysis. Conclusions. Analysis of satellite images of the spit made it possible to distinguish three periods in the history of the Bakalskaya Spit evolution: 1985–1997, 1998–2007 and 2007–2016. The first period was characterized by relative stability. The strongest erosion took place in 1998; after that the alluvial and erosion cases alternated for 10 years weakly tending to general erosion that constituted the second period. The third one that began in 2007 can be defined as the period of spit degradation accompanied by the irreversible loss of beach material. The basic parameters conditioning hydrodynamics of the Bakalskaya Spit water area are: total duration of storms; average and maximum values of significant heights of wind waves and swell. Statistical characteristics of the wind waves’ parameters are of a fairly strong inter-annual variability. According to the average and maximum indices, the wind waves directed close to the normal to the coastline (WSW and WNW) are the most developed. The applied discriminant analysis permitted to draw a statistically reliable conclusion that the direction of the final (average annual) wave impact on the coastal zone, conditioning the processes of sand accumulation or erosion was set by the waves directed to NNW, at that the swell contribution was dominant. The impact degree is conditioned by strong storms with the directions close to the normal to the coastline, namely, the WSW ones

scholarly journals Loop-Type Wave-Generation Method for Generating Wind Waves under Long-Fetch Conditions

2017 ◽  
Vol 34 (10) ◽  
pp. 2129-2139 ◽  
Author(s):  
Naohisa Takagaki ◽  
Satoru Komori ◽  
Mizuki Ishida ◽  
Koji Iwano ◽  
Ryoichi Kurose ◽  
...  
Keyword(s):  
Wind Wave ◽  
Wind Waves ◽  
Peak Frequency ◽  
Wave Generation ◽  
New Wave ◽  
Wave Tank ◽  
Irregular Wave ◽  
Wind Speeds ◽  
Type Wave ◽  
Wave Generator

AbstractIt is important to develop a wave-generation method for extending the fetch in laboratory experiments, because previous laboratory studies were limited to the fetch shorter than several dozen meters. A new wave-generation method is proposed for generating wind waves under long-fetch conditions in a wind-wave tank, using a programmable irregular-wave generator. This new method is named a loop-type wave-generation method (LTWGM), because the waves with wave characteristics close to the wind waves measured at the end of the tank are reproduced at the entrance of the tank by the programmable irregular-wave generator and the mechanical wave generation is repeated at the entrance in order to increase the fetch. Water-level fluctuation is measured at both normal and extremely high wind speeds using resistance-type wave gauges. The results show that, at both wind speeds, LTWGM can produce wind waves with long fetches exceeding the length of the wind-wave tank. It is observed that the spectrum of wind waves with a long fetch reproduced by a wave generator is consistent with that of pure wind-driven waves without a wave generator. The fetch laws between the significant wave height and the peak frequency are also confirmed for the wind waves under long-fetch conditions. This implies that the ideal wind waves under long-fetch conditions can be reproduced using LTWGM with the programmable irregular-wave generator.

Wave tank study of phase velocities and damping of gravity-capillary wind waves in the presence of surface films

2006 ◽  
pp. 129-143 ◽  
Author(s):  
Stanislav A. Ermakov ◽  
Irina A. Sergievskaya ◽  
Emma M. Zuikova ◽  
Vladimir Yu. Goldblat ◽  
Yury B. Shchegolkov
Keyword(s):  
Wind Waves ◽  
Surface Films ◽  
Wave Tank ◽  
Phase Velocities

scholarly journals The Effect of Draft Ratio of Side-By-Side Barges on Fluid Oscillation in Narrow Gap

2020 ◽  
Vol 8 (9) ◽  
pp. 694
Author(s):  
Linfeng Chen ◽  
Xueshen Cao ◽  
Shiyan Sun ◽  
Jie Cui
Keyword(s):  
Resonant Frequency ◽  
Oscillation Amplitude ◽  
Numerical Results ◽  
Floating Body ◽  
Fluid Viscosity ◽  
Depth Range ◽  
Narrow Gap ◽  
Wave Tank ◽  
Fluid Oscillation ◽  
Viscous Fluid Model

In the present study, the effects of the draft ratio of the floating body on the fluid oscillation in the gap are investigated by using the viscous fluid model. Numerical simulations are implemented by coupling wave2Foam and OpenFOAM. The Volume of Fluid (VOF) model is used to capture the free surface waves. It is verified that the numerical results agree well with the experimental and other results. It is firstly found that, within the water depth range investigated in the present study, the depth of the wave tank has a significant effect on the numerical results. As the depth of the wave tank increases, the oscillation amplitude of the narrow-gap fluid largely decreases and the resonant frequency of the fluid oscillation in the narrow gap increases. The results also reveal that the draft ratio of floating bodies has a significant nonlinear influence on the resonant frequency and on the oscillation amplitude of the fluid in the narrow gap. With an increase in the draft of either the floating body on the wave side or the one on the back wave side, the resonant frequency decreases. The increase in the draft of the floating body on the wave side causes an increase in the reflection wave coefficient and leads to a drop in the fluid oscillation amplitude, and the increase in the draft of the floating body on the back wave side triggers a decrease in the reflection wave coefficient and results in an increase in the fluid oscillation amplitude. Meanwhile, the viscous dissipation induced by the fluid viscosity synchronously increases with the oscillation amplitude of the fluid in the increasing gap. Moreover, it is found that the draft ratio mainly affects the horizontal force of the floating body on the back wave side and that the highest calculated force increases with the draft ratio.

scholarly journals On Evolution of Young Wind Waves in Time and Space

Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 562 ◽  
Author(s):  
Shemer
Keyword(s):  
Wave Field ◽  
Field Experiments ◽  
Wind Wave ◽  
Wind Waves ◽  
Wave Generation ◽  
Wind Forcing ◽  
Spatial And Temporal Variation ◽  
Extensive Discussion ◽  
Deterministic Theory ◽  
Theoretical Approaches

The mechanisms governing the evolution of the wind-wave field in time and in space are not yet fully understood. Various theoretical approaches have been offered to model wind-wave generation. To examine their validity, detailed and accurate experiments under controlled conditions have to be carried out. Since it is next to impossible to get the required control of the governing parameters and to accumulate detailed data in field experiments, laboratory studies are needed. Extensive previously unavailable results on the spatial and temporal variation of wind waves accumulated in our laboratory under a variety of wind-forcing conditions and using diverse measuring techniques are reviewed. The spatial characteristics of the wind-wave field were determined using stereo video imaging. The turbulent airflow above wind waves was investigated using an X-hot film. The wave field under steady wind forcing as well as evolving from rest under impulsive loading was studied. An extensive discussion of the various aspects of wind waves is presented from a single consistent viewpoint. The advantages of the stochastic approach suggested by Phillips over the deterministic theory of wind-wave generation introduced by Miles are demonstrated. Essential differences between the spatial and the temporal analyses of wind waves’ evolution are discussed, leading to examination of the applicability of possible approaches to wind-wave modeling.

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