Optimization of Segmented Wave-Maker Control to Generate Spatially Uniform Regular Waves in a Rounded-Rectangular Wave Basin

2021 ◽  
Author(s):  
Daichi Ota ◽  
Hidetaka Houtani ◽  
Hiroshi Sawada ◽  
Harukuni Taguchi
Keyword(s):  
Wave Field ◽  
Wave Height ◽  
Simulated Annealing Algorithm ◽  
Optimal Solution ◽  
Optimization Method ◽  
Linear Wave ◽  
Wave Direction ◽  
Wave Basin ◽  
Test Zone ◽  
Wave Maker

Abstract A wave field in a wave basin inevitably has spatial variation due to the wave’s cylindrical propagation property. Therefore, we aimed to develop an optimization method for the control of wave-makers to produce a spatially uniform wave field in a specified test zone inside a wave basin with an arbitrary arrangement of wave-makers. The optimization is based on the simulated annealing algorithm, a method for finding a globally optimal solution, which was combined with a numerical wave basin based on linear wave-maker theory. A wave generation experiment was performed in the actual sea model basin (80 m long, 40 m wide, and 4.5 m deep) at the National Maritime Research Institute to validate the proposed optimization method. A case study was conducted with a long-crested regular-wave with a wave height of 10 cm, wavelength of 4.0 m, and wave direction of 180 degrees, which corresponds to the longitudinal direction of the wave basin. A 40-m × 14-m test zone was set in the middle of the wave basin. The experimental results with and without the proposed optimization were compared, which confirmed that the spatial uniformity of the wave field was improved, and the coefficient of variation for the wave height in the test zone decreased from 0.127 to 0.029.

Climatologically Modeled Wave Field Analyses in the Western South Atlantic

2009 ◽  
Author(s):  
Eric Oliveira Ribeiro ◽  
Marcelo Andrioni ◽  
Renato Parkinson Martins ◽  
Guisela Grossmann Matheson ◽  
Jose´ Henrique Alves ◽  
...  
Keyword(s):  
High Pressure ◽  
Wave Field ◽  
Wave Height ◽  
Extreme Values ◽  
South Atlantic ◽  
Structure Design ◽  
Plant Design ◽  
Wave Direction ◽  
Pressure Center ◽  
Predominant Direction

Wave height, period and direction are basic parameters for designing off-shore structures. Besides this direct application, knowledge of the regional characteristics of a wave field can also help in the selection of optimal regions for wave power energy plant design and installation. A wave climatology based on data generated by a WAVEWATCH III model simulation (NOAA WW3) for the Brazilian coast was analyzed and validated against statistical values derived from opportunity vessel measurements. The hindcast covered the period from January 1997 to December 2005 in a region between 5°N – 40°S and 10°W – 65°W. The grid used was uniform with a 0.25° spacial resolution. The boundary conditions were obtained from NOAA WW3 operational model and the atmospheric forcing from NOAA GFS model. The model results were calibrated with field data and detailed information about the simulation can be obtained in Alves et al. (2008) and Alves et al. (in press). Monthly averages of significant height, period and wavelength were calculated using 3 hour time resolution fields. Since a simple mean direction has small physical representativeness, the predominant direction (moda) and associated persistency were obtained from the data. The results were then compared with values from the U.S. Navy Marine Climate Atlas of the World. This Atlas has four points located within the selected model grid region. These points showed good agreement with wave period, height and direction persistency based on the WW3 simulation results. The wave climatology showed that the predominant wave direction from April to July was from S and SE in southern Brazil, associated with swells related to cold fronts. The S and SE swells were also responsible for the largest mean wave height (2.1 m) observed in the climatology. Another result that was validated with the literature was the E and NE predominant wave direction during the austral summer. This phenomenon is associated with winds originated from the South Atlantic High Pressure Center, which is a semi permanent high pressure center near Trindade Island. The wave climate in northern Brazil showed a predominant direction from the N during January to March, associated with the northern hemisphere winter storms. During the remaining months of the year, the predominant wave direction is E and NE associated with trade winds. The model results are still in a processing phase to produce extreme values, which will be more useful for coastal and off-shore structure design.

A Phase-Amplitude Iteration Scheme for the Optimization of Deterministic Wave Sequences

2009 ◽  
Author(s):  
Christian Schmittner ◽  
Sascha Kosleck ◽  
Janou Hennig
Keyword(s):  
Target Location ◽  
Wave Train ◽  
Target Position ◽  
Wave Theory ◽  
Iteration Scheme ◽  
Linear Wave ◽  
Linear Wave Theory ◽  
Wave Basin ◽  
Wave Maker ◽  
Phase Amplitude

For the deterministic investigation of extreme events like capsizing, broaching or wave impacts, methods for the generation of deterministic wave sequences are required. These wave sequences can be derived from full scale measurements, numerical simulations or other sources. Most methods for the generation of deterministic wave sequences rely as a backbone on linear wave theory for the backwards transformation of the wave train from the target position in the wave basin to the position of the wave maker. This implies that nonlinear wave effects are not covered to full extend or they are completely neglected. This paper presents a method to improve the quality of the generated wave train via an experimental optimization. Based on a first wave sequence generated with linear wave theory and measured in the wave basin, the phases and amplitudes of the wave maker control signal are modified in frequency domain. The iteration scheme corrects both, shifts in time and in location, resulting in an improved deterministic wave train at the target location. The paper includes results of this method from three different basins with different types of wave generators, water depth and model scales. In addition, this method is applied to a numerical wave tank where the waves can be optimized before the actual basin testing.

scholarly journals ÁP DỤNG MÔ HÌNH SWAN DỰ BÁO TRƯỜNG SÓNG VEN BỜ BIỂN HẢI PHÒNG

2019 ◽  
Vol 19 (1) ◽  
pp. 41-48
Author(s):  
Le Duc Cuong
Keyword(s):  
Wave Field ◽  
Wave Height ◽  
Coastal Area ◽  
Rainy Season ◽  
Dry Season ◽  
Maximum Height ◽  
Wave Direction ◽  
Swan Model ◽  
Dominant Wave ◽  
Near Shore

This paper presents some results of studying the SWAN model, and application of SWAN model to simulate wave field representative of the rainy season and dry season in the coastal area of Hai Phong. During the dry season, the dominant wave direction is in a range from 60o to 100o, maximum height of waves near shore is in a range from 1,0 m to 1,5 m with wavelength of about 2,0 m to 5,0 m, maximum height of waves offshore is in a range from 2,0 m to 2,5 m with wavelength of about 6,0 m to 16 m. During the rainy season, wave height near shore is in a range from 0,2 m to 0,6 m, and that offshore is in a range from 0,8 m to 1,4 m, maximum height of waves is about 3,4 m, predominant wave directions in this season are E, SE and S. In this scenario that predicts waves generated by storms, wave height offshore is in a range from 8,0 m to 10 m with wavelength of about 60 m, and that near shore is in a range from 2,0 m to 4,0 m with wavelength of about 10–20 m.

Multidisciplinary Object Compatibility Design Optimization Based on Simulated Annealing Algorithm

2012 ◽  
Vol 490-495 ◽  
pp. 2515-2519
Author(s):  
Bi Qiang Yu ◽  
Xiao Qun Wang ◽  
Lin Hao Wang
Keyword(s):  
Simulated Annealing ◽  
Design Optimization ◽  
Optimization Design ◽  
Simulated Annealing Algorithm ◽  
Optimal Solution ◽  
Optimization Method ◽  
System Level ◽  
Program Termination ◽  
Annealing Algorithm ◽  
Basic Ideas

In studying Multidisciplinary Object Compatibility Design Optimization method for non-hierarchic system, Simulated Annealing algorithm is introduced to establish system level model , and the basic ideas and working principle is given. In the optimization of system level, the coupling relationship between different subsystems is improved by state accepting function which is embedded in constraint. In this way, abnormal program termination and premature convergence will be avoided and ideal global optimal solution will be achieved effectually. Then the method is proved by used in the optimization design of pendulous micromechanical accelerometer

An Improved Simulated Annealing Algorithm Based on Genetic Algorithm

2012 ◽  
Vol 490-495 ◽  
pp. 267-271 ◽  
Author(s):  
Shu Fei Li
Keyword(s):  
Genetic Algorithm ◽  
Simulated Annealing ◽  
Reservoir Operation ◽  
Simulated Annealing Algorithm ◽  
Optimal Solution ◽  
Optimization Method ◽  
Operation Speed ◽  
Ga Algorithm ◽  
Hybrid Simulated Annealing ◽  
Annealing Algorithm

An effective hybrid Simulated Annealing Algorithm based on Genetic Algorithm is proposed to apply to reservoir operation. Compared with other optimal methods, it is proved that SA-GA algorithm is a quite effective optimization method to solve reservoir operation problem. The simulated annealing algorithm is introduced to Genetic Algorithm, which is feasibility and validity. As a result of stronger ability of global search and better convergence property of SA-GA, and compared with other algorithms, the approximate global optimal solution would be obtained in little time. The operation speed is more quickness and the results are more stabilization by SA-GA, than Genetic Algorithm and the traditional Dynamic Programming and POA.

Optimization of Short-Crested Deterministic Wave Sequences via a Phase-Amplitude Iteration Scheme

2012 ◽  
Author(s):  
Christian Schmittner ◽  
Janou Hennig
Keyword(s):  
Target Location ◽  
Wave Train ◽  
Target Position ◽  
Wave Theory ◽  
Iteration Scheme ◽  
Linear Wave ◽  
Linear Wave Theory ◽  
Wave Basin ◽  
Wave Maker ◽  
Phase Amplitude

For the deterministic investigation of rare phenomena like capsizing, broaching or wave impacts, methods for the generation of deterministic wave sequences are required. These wave sequences can be derived from full scale measurements, numerical simulations or other sources. Most methods for the generation of deterministic wave sequences rely as a backbone on linear wave theory for the upstream transformation of the wave train from the target position in the wave basin to the position of the wave maker. This implies that nonlinear wave effects are not covered to a full extend or completely neglected. This paper presents the extension of a method for the generation of deterministic waves presented during OMAE 2009. The method improves the quality of the generated wave train via an experimental optimization. Based on a first wave sequence generated with linear wave theory and measured in the wave basin, the phases and amplitudes of the wave maker control signal are modified in frequency domain. The iteration scheme corrects for both shifts in time and in location resulting in an improved deterministic wave train at the target location. The method is extended to short-crested seas. The paper includes results of this method applied to a 3D wave basin.

The Concept of the Optimum Alignment of Discharge Pipelines Due to the Minimization of the Wave Forces

1992 ◽  
Vol 25 (9) ◽  
pp. 211-216
Author(s):  
A. Akyarli ◽  
Y. Arisoy
Keyword(s):  
Wave Height ◽  
Wave Force ◽  
Wave Forces ◽  
Wave Direction ◽  
Incoming Wave ◽  
Pipeline Route ◽  
Optimum Alignment ◽  
The Cost ◽  
Resultant Wave

As the wave forces are the function of the wave height, period and the angle between the incoming wave direction and the axis of the discharge pipeline, the resultant wave force is directly related to the alignment of the pipeline. In this paper, a method is explained to determine an optimum pipeline route for which the resultant wave force becomes minimum and hence, the cost of the constructive measures may decrease. Also, the application of this method is submitted through a case study.

scholarly journals Optimal solution of the fractional order breast cancer competition model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
H. Hassani ◽  
J. A. Tenreiro Machado ◽  
Z. Avazzadeh ◽  
E. Safari ◽  
S. Mehrabi
Keyword(s):  
Breast Cancer ◽  
Fractional Order ◽  
Legendre Polynomials ◽  
Numerical Experiments ◽  
Optimal Solution ◽  
Optimization Method ◽  
Competition Model ◽  
Basis Functions ◽  
Cell Populations ◽  
Operational Matrices

AbstractIn this article, a fractional order breast cancer competition model (F-BCCM) under the Caputo fractional derivative is analyzed. A new set of basis functions, namely the generalized shifted Legendre polynomials, is proposed to deal with the solutions of F-BCCM. The F-BCCM describes the dynamics involving a variety of cancer factors, such as the stem, tumor and healthy cells, as well as the effects of excess estrogen and the body’s natural immune response on the cell populations. After combining the operational matrices with the Lagrange multipliers technique we obtain an optimization method for solving the F-BCCM whose convergence is investigated. Several examples show that a few number of basis functions lead to the satisfactory results. In fact, numerical experiments not only confirm the accuracy but also the practicability and computational efficiency of the devised technique.

A CFD Study of Focused Extreme Wave Impact on Decks of Offshore Structures

2014 ◽  
Author(s):  
Xin Lu ◽  
Pankaj Kumar ◽  
Anand Bahuguni ◽  
Yanling Wu
Keyword(s):  
Real World ◽  
Offshore Structures ◽  
Air Gap ◽  
Irregular Waves ◽  
Linear Wave ◽  
Extreme Wave ◽  
Wave Impact ◽  
Loading Test ◽  
Wide Range ◽  
Wave Maker

The design of offshore structures for extreme/abnormal waves assumes that there is sufficient air gap such that waves will not hit the platform deck. Due to inaccuracies in the predictions of extreme wave crests in addition to settlement or sea-level increases, the required air gap between the crest of the extreme wave and the deck is often inadequate in existing platforms and therefore wave-in-deck loads need to be considered when assessing the integrity of such platforms. The problem of wave-in-deck loading involves very complex physics and demands intensive study. In the Computational Fluid Mechanics (CFD) approach, two critical issues must be addressed, namely the efficient, realistic numerical wave maker and the accurate free surface capturing methodology. Most reported CFD research on wave-in-deck loads consider regular waves only, for instance the Stokes fifth-order waves. They are, however, recognized by designers as approximate approaches since “real world” sea states consist of random irregular waves. In our work, we report a recently developed focused extreme wave maker based on the NewWave theory. This model can better approximate the “real world” conditions, and is more efficient than conventional random wave makers. It is able to efficiently generate targeted waves at a prescribed time and location. The work is implemented and integrated with OpenFOAM, an open source platform that receives more and more attention in a wide range of industrial applications. We will describe the developed numerical method of predicting highly non-linear wave-in-deck loads in the time domain. The model’s capability is firstly demonstrated against 3D model testing experiments on a fixed block with various deck orientations under random waves. A detailed loading analysis is conducted and compared with available numerical and measurement data. It is then applied to an extreme wave loading test on a selected bridge with multiple under-deck girders. The waves are focused extreme irregular waves derived from NewWave theory and JONSWAP spectra.

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