Numerical Study of Wave Diffraction with Four Cylinders

2014 ◽  
Vol 638-640 ◽  
pp. 1758-1762
Author(s):  
Bao Lei Geng ◽  
Ci Heng Zhang
Keyword(s):  
Mathematical Model ◽  
Incident Wave ◽  
Numerical Study ◽  
Wave Force ◽  
Wave Direction ◽  
Linear Waves ◽  
The Given ◽  
Four Cylinders ◽  
Incident Wave Direction ◽  
Origin Point

By taking the 3D Laplace equation as the basic governing equation, a mathematical model with respect to the interaction between linear waves and arbitrary 3D structures was founded. With an example of wave action with four cylinders, numerical results show that when incident wave direction is 22.5°, wave force Fx on 1# cylinder and 2# cylinder is the biggest and when incident wave direction is 0°, wave force Fx on 3# cylinder and 4# cylinder is the biggest; wave force Fy and the wave height on origin point increases with incident wave direction increasing for the given layout and incident wave conditions.

Hydrodynamic Analysis of Oil Storage Vessels for National Strategic Petroleum Reserve

2011 ◽  
Vol 291-294 ◽  
pp. 2541-2551
Author(s):  
Gang Jun Zhai ◽  
Yong Cheng ◽  
Wen Hua Wang ◽  
Yi Huang
Keyword(s):  
Incident Wave ◽  
Vertical Direction ◽  
Time History ◽  
Wave Force ◽  
Mooring System ◽  
Wave Direction ◽  
Storage Vessel ◽  
Oil Storage ◽  
Motion Responses ◽  
Incident Wave Direction

This paper expatiates hydrodynamic time-domain analysis on strategic oil storage vessels in free floating condition or with dolphin-fender mooring system by means of AQWA numerical software. The results indicate that motion responses of the oil storage vessel with dolphin-fender mooring have improved significantly. The time-history of wave diffraction forces in incident wave direction are basically consistent between the free floating and moored condition. However, in vertical direction of incident wave, the diffraction wave force of the oil storage vessel in free floating condition is obviously different from that with mooring system, which is the result of the coupling interaction between dolphin and vessels. Mooring forces include fender reaction and cable tension, as for which dominate, it depend on evocable motion responses about incident wave direction.

Homogeneous near-perfect invisible ground and free space cloak

2017 ◽  
Vol 31 (09) ◽  
pp. 1750059 ◽  
Author(s):  
Mohamad Fazeli ◽  
Seyyed Hassan Sedighy ◽  
Hamid Reza Hassani
Keyword(s):  
Incident Wave ◽  
Free Space ◽  
Single Step ◽  
Wave Direction ◽  
Transformation Theory ◽  
Design Flexibility ◽  
Mapping Process ◽  
Optical Transformation ◽  
Constitutive Parameters ◽  
Incident Wave Direction

A general approach to design near perfect invisible ground and free space cloaks is introduced in this paper. The proposed method which is based on the optical transformation theory, leads to homogeneous constitutive parameters for the cloaks without any singularities. Moreover, the single-step mapping process with linear relations achieves an uncomplicated designing process. Invisibility performance obtained by using this approach does not depend on the incident wave direction, also. The simplicity and design flexibility of the introduced approach with the homogeneity of extracted parameters greatly facilitate the design and fabrication processes of the both proposed ground and free space invisible cloaks. The numerical simulations prove the capability and universality of the proposed design approach.

scholarly journals Homogeneous Wave Load Effects on the Connections of Main Parts of Side-Anchored Straight Floating Bridge

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Meysam Rajabi ◽  
Hassan Ghassemi ◽  
Hamidreza Ghafari
Keyword(s):  
Hydrodynamic Interaction ◽  
Numerical Study ◽  
Wave Force ◽  
Wave Forces ◽  
Mooring System ◽  
Wave Direction ◽  
Wave Load ◽  
Mooring Lines ◽  
Homogeneous Wave ◽  
Floating Bridge

In this paper, a numerical study is presented to investigate wave force on the connections of main parts of a side-anchored straight floating bridge concept for the Bjørnafjorden fjord crossing. The floating bridge is supported by 18 pontoons, and three groups of mooring lines are employed to restrain the bridge against horizontal loads and increase its transverse stiffness. The created wave forces at the connections of pontoon-column and column-girder of the floating bridge considering the effects of short-crested and long-crested waves, varying wave direction, hydrodynamic interaction between pontoons, and mooring system are analyzed. It is found that short-crested and long-crested waves depending on their direction decrease or increase the wave forces on the joints. Considering that the effect of hydrodynamic interaction between pontoons can increase or reduce the wave forces and moments created in the joints, which means the neglect of the hydrodynamic interaction effects between the pontoons to simplify the modeling of this type of floating bridge, may be unacceptable. Moreover, the results showed that the bridge mooring system does not merely reduce the wave forces and moments at joints along the bridge.

scholarly journals Near Trapping Effect on Wave-Power Extraction by Linear Periodic Arrays

2019 ◽  
Vol 12 (1) ◽  
pp. 29
Author(s):  
Dezhi Ning ◽  
Zechen He ◽  
Ying Gou ◽  
Malin Göteman
Keyword(s):  
Incident Wave ◽  
Wave Energy ◽  
Hydrodynamic Interaction ◽  
Wave Power ◽  
Wave Direction ◽  
Power Extraction ◽  
Periodic Arrays ◽  
Wave Energy Converters ◽  
Incident Wave Direction ◽  
Energy Converters

Near trapping is a kind of strong hydrodynamic interaction phenomenon in a regular array under specific incident wave conditions, which causes the excitation force on the structures in the array to change suddenly. In this paper, based on linear potential flow theory, the effects of near trapping on the hydrodynamic interaction and wave-power extraction characteristics of linear periodic arrays composed of the oscillating float type wave energy converters are studied by using the higher-order boundary element method in a frequency domain. The parameters considered include the separation spacing, number of devices, and incident wave direction. It is found that the near trapping significantly reduces the overall wave-power extraction, especially for the cases with a large number of devices, and changes the trend of the power distribution. The occurrence of the near trapping phenomenon depends on the ratio of the separation spacing to the wavelength and the incident wave direction. The results highlight the effective layout of linear arrays under the influence of near trapping, which not only ensures the total production power, but also reduces the power difference among wave energy converters.

scholarly journals PREDICTION OF DEVELOPMENT OF SAND SPITS AND CUSPATE FORELANDS WITH RHYTHMIC SHAPES CAUSED BY SHORELINE INSTABILITY USING BG MODEL

2012 ◽  
Vol 1 (33) ◽  
pp. 35 ◽  
Author(s):  
Masumi Serizawa ◽  
Takaaki Uda ◽  
Shiho Miyahara
Keyword(s):  
Probability Distribution ◽  
Incident Wave ◽  
Three Dimensional ◽  
High Angle ◽  
Dimensional Model ◽  
Wave Direction ◽  
Three Dimensional Model ◽  
Wave Instability ◽  
Shoreline Evolution ◽  
Incident Wave Direction

The BG model (a three-dimensional model for predicting beach changes based on Bagnold’s concept) was used to simulate the shoreline evolution caused by the high-angle wave instability discussed by Ashton et al. Three calculations were carried out: the wave direction was assumed to be obliquely incident from 60˚ counterclockwise (Case 1) or from the directions of ±60˚ with probabilities of 0.5:0.5 (Case 2) and 0.65:0.35 (Case 3), while determining the incident wave direction from the probability distribution at each step. The three-dimensional development of multiple sand spits and cuspate forelands with rhythmic shapes was successfully explained using the BG model. The results of the previous study conducted by Ashton et al. were reconfirmed and reinforced.

NUMERICAL STUDY FOR THAILAND: MATHEMATICAL MODEL OF PRODUCTION AND LOGISTIC PLANNING FOR SUGARCANES USED IN BIOFUEL PRODUCTION

2013 ◽  
Author(s):  
Pancheewa Benjamasutin ◽  
◽  
Ponthong Rijana ◽  
Phongchayont Srisuwan ◽  
Aussadavut Dumrongsiri
Keyword(s):  
Mathematical Model ◽  
Numerical Study ◽  
Biofuel Production ◽  
Logistic Planning

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 Computer Modeling of Aerosol Emissions Spread in the Atmosphere

2019 ◽  
Vol 97 ◽  
pp. 05023 ◽  
Author(s):  
Daler Sharipov ◽  
Sharofiddin Aynakulov ◽  
Otabek Khafizov
Keyword(s):  
Boundary Layer ◽  
Mathematical Model ◽  
Atmospheric Boundary Layer ◽  
Computer Modeling ◽  
Numerical Experiments ◽  
Climatic Factors ◽  
Numerical Algorithms ◽  
Aerosol Emissions ◽  
The Given ◽  
And Diffusion

The paper deals with the development of mathematical model and numerical algorithms for solving the problem of transfer and diffusion of aerosol emissions in the atmospheric boundary layer. The model takes into account several significant parameters such as terrain relief, characteristics of underlying surface and weather-climatic factors. A series of numerical experiments were conducted based on the given model. The obtained results presented here show how these factors affect aerosol emissions spread in the atmosphere.

A Numerical Study of Unsteady Natural Convection in a Rectangular Enclosure: The Effect of Compressibility

2004 ◽  
Author(s):  
K. M. Akyuzlu ◽  
Y. Pavri ◽  
A. Antoniou
Keyword(s):  
Mathematical Model ◽  
Stokes Equations ◽  
Numerical Study ◽  
Vertical Wall ◽  
Ideal Gas ◽  
Working Fluid ◽  
Two Dimensional ◽  
Algebraic Equations ◽  
Rectangular Enclosure ◽  
Circulation Patterns

A two-dimensional, mathematical model is adopted to investigate the development of buoyancy driven circulation patterns and temperature contours inside a rectangular enclosure filled with a compressible fluid (Pr=1.0). One of the vertical walls of the enclosure is kept at a higher temperature then the opposing vertical wall. The top and the bottom of the enclosure are assumed insulated. The physics based mathematical model for this problem consists of conservation of mass, momentum (two-dimensional Navier-Stokes equations) and energy equations for the enclosed fluid subjected to appropriate boundary conditions. The working fluid is assumed to be compressible through a simple ideal gas relation. The governing equations are discretized using second order accurate central differencing for spatial derivatives and first order forward finite differencing for time derivatives where the computation domain is represented by a uniform orthogonal mesh. The resulting nonlinear equations are then linearized using Newton’s linearization method. The set of algebraic equations that result from this process are then put into a matrix form and solved using a Coupled Modified Strongly Implicit Procedure (CMSIP) for the unknowns (primitive variables) of the problem. A numerical experiment is carried out for a benchmark case (driven cavity flow) to verify the accuracy of the proposed solution procedure. Numerical experiments are then carried out using the proposed compressible flow model to simulate the development of the buoyancy driven circulation patterns for Rayleigh numbers between 103 and 105. Finally, an attempt is made to determine the effect of compressibility of the working fluid by comparing the results of the proposed model to that of models that use incompressible flow assumptions together with Boussinesq approximation.

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