Analytical and Numerical Study of Nearshore Multiple Oscillating Water Columns

2013 ◽  
Author(s):  
Kourosh Rezanejad ◽  
Joydip Bhattacharjee ◽  
C. Guedes Soares
Keyword(s):  
Water Depth ◽  
Numerical Study ◽  
Integral Equation Method ◽  
Wave Theory ◽  
Boundary Integral ◽  
Water Columns ◽  
Finite Water Depth ◽  
Cartesian Coordinate ◽  
Oscillating Water Columns ◽  
Good Agreement

In the present study, the performance of two chamber nearshore oscillating water columns (OWCs) in finite water depth is analyzed based on the linearized water wave theory in the two dimensional Cartesian coordinate systems. The barriers are assumed to be fixed and the turbine characteristics are assumed linear with respect to the fluctuations of volume flux and pressure inside the chamber. The free surface inside the chambers is modeled as a non-plane wave surface. Two different mathematical models are employed to solve the hydrodynamic problem; the semi-analytic method of matched eigenfunction expansion and the numerical scheme of Boundary Integral Equation Method (BIEM). The numerical results are compared with the semi-analytic results and show good agreement. The effects of the distance between the barriers and the length of the barriers on the efficiency of the OWC device are investigated. The results of two chambers OWC are also compared with the results for an equivalent single OWC chamber. Further, the effect of the water depth on the capacity of the wave power absorption is discussed.

Analytical and Numerical Study of Nearshore Multiple Oscillating Water Columns

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Kourosh Rezanejad ◽  
Joydip Bhattacharjee ◽  
Carlos Guedes Soares
Keyword(s):  
Water Depth ◽  
Numerical Study ◽  
Integral Equation Method ◽  
Wave Theory ◽  
Boundary Integral ◽  
Water Columns ◽  
Finite Water Depth ◽  
Cartesian Coordinate ◽  
Oscillating Water Columns ◽  
Good Agreement

In the present study, the performance of two chamber nearshore oscillating water columns (OWCs) in finite water depth is analyzed based on the linearized water wave theory in the two-dimensional Cartesian coordinate systems. The barriers are assumed to be fixed and the turbine characteristics are assumed linear with respect to the fluctuations of volume flux and pressure inside the chamber. The free surface inside the chambers is modeled as a nonplane wave surface. Two different mathematical models are employed to solve the hydrodynamic problem: the semi-analytic method of matched eigenfunction expansion and the numerical scheme of boundary integral equation method (BIEM). The numerical results are compared with the semi-analytic results and show good agreement. The effects of the distance between the barriers and the length of the barriers on the efficiency of the OWC device are investigated. The results of two chambers OWC are also compared with the results for an equivalent single OWC chamber. Further, the effect of the water depth on the capacity of the wave power absorption is discussed.

scholarly journals A NUMERICAL STUDY ON MULTI-CHAMBER OSCILLATING WATER COLUMNS

2015 ◽  
Vol 3 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Pallav KOIRALA ◽  
Shuichi NAGATA ◽  
Yasutaka IMAI ◽  
Tengen MURAKAMI ◽  
Toshiaki SETOGUCHI
Keyword(s):  
Numerical Study ◽  
Water Columns ◽  
Oscillating Water Columns

Numerical Study on the Growth and Collapse of a Cavitation Bubble inside a Rigid Cylinder with a Compliant Coating

2014 ◽  
Vol 875-877 ◽  
pp. 1194-1198
Author(s):  
Fardin Rouzbahani ◽  
M.T. Shervani-Tabar
Keyword(s):  
Integral Equation ◽  
Boundary Integral Equation ◽  
Cavitation Bubble ◽  
Numerical Study ◽  
Finite Difference Methods ◽  
Life Time ◽  
Integral Equation Method ◽  
Boundary Integral ◽  
Compliant Coating ◽  
Rigid Cylinder

In this paper, growth and collapse of a cavitation bubble inside a rigid cylinder with a compliant coating (a model of humans vessels) is studied using Boundary Integral Equation and Finite Difference Methods. The fluid flow is treated as a potential flow and Boundary Integral Equation Method is used to solve Laplaces equation for velocity potential. The compliant coating is modeled as a membrane with a spring foundation. The effects of the parameters describing the flow and the parameters describing the compliant coating on the interaction between the fluid and the cylindrical compliant coating are shown throughout the numerical results. It is shown that by increasing the compliancy of the coating, the bubble life time is decreased and the mass per unit area has an important role in bubble behavior.

Wave Scattering From Multiple Horizontal Plates as a Breakwater

2009 ◽  
Author(s):  
Guoyu Wang ◽  
Yongxue Wang
Keyword(s):  
Water Depth ◽  
Plate Thickness ◽  
Wave Theory ◽  
Linear Potential ◽  
Antisymmetric Part ◽  
Transmission Coefficients ◽  
Present Solution ◽  
Relative Water ◽  
Constant Coefficients ◽  
Finite Water Depth

The multiple horizontal plates breakwater is proposed in this article, which mainly consists of several horizontal plates. The regular wave test results demonstrate that it has good performance of dissipating waves. Based on the linear potential wave theory, the scattering of waves normally incident on the multiple horizontal plates in a channel of finite water depth is investigated. The velocity potential is split to the symmetric and antisymmetric part, and the method of eigenfunction expansions is used to obtain the unknown constant coefficients determined from the matching conditions. The thickness of the plates is considered in the theoretical analysis. The present solution is compared with the existing theoretical, numerical and experimental results with good agreements. The parameters such as the relative water depth, relative plate width, relative plate thickness and number of plates, those identified with the performance of the breakwater are investigated and discussed. The variation of reflection and transmission coefficients alone with the above mentioned parameters are also presented.

Linear Evolution of a Narrow-Banded Surface Gravity Wavepacket Over an Infinite Step

2019 ◽  
Author(s):  
Yan Li ◽  
Thomas A. A. Adcock ◽  
Ton S. van den Bremer
Keyword(s):  
Water Depth ◽  
Evolution Equations ◽  
Multiple Scales ◽  
Fundamental Problem ◽  
Wave Theory ◽  
Second Order ◽  
Order Effects ◽  
Linear Evolution ◽  
Finite Water Depth ◽  
Higher Order Effects

Abstract This paper focuses on the classical and fundamental problem of waves propagating over an infinite step in finite water depth. Specifically, this paper aims to extend classical narrow-banded wave theory for constant water depth which uses a multiple-scales expansion to the case of an abrupt change in the water depth, known as an infinite step. This paper derives the linear evolution equations and is the first step towards the calculation of second-order and higher-order effects for wavepackets travelling over a step using commonly employed envelope-type evolution equations, in particular the bound sub- and super-harmonics at second order.

Numerical study of Rogue waves as nonlinear Schrödinger breather solutions under finite water depth

Wave Motion ◽  
2015 ◽  
Vol 52 ◽  
pp. 81-90 ◽  
Author(s):  
Zhe Hu ◽  
Wenyong Tang ◽  
Hongxiang Xue ◽  
Xiaoying Zhang
Keyword(s):  
Water Depth ◽  
Numerical Study ◽  
Rogue Waves ◽  
Nonlinear Schrödinger ◽  
Finite Water Depth

A Numerical Study of Wave Energy Converter in the Form of an Oscillating Water Column Based on a Mixed Eulerian-Lagrangian Formulation

2010 ◽  
Author(s):  
Chunrong Liu ◽  
Zhenhua Huang ◽  
Adrian Law Wing Keung ◽  
Nan Geng
Keyword(s):  
Water Column ◽  
Wave Energy ◽  
Numerical Study ◽  
Integral Equation Method ◽  
Boundary Integral ◽  
Lagrangian Formulation ◽  
Oscillating Water Column ◽  
Extraction Chamber ◽  
Air Chamber ◽  
Air Turbine

A desingularized boundary integral equation method (DBIEM) is employed to study the wave energy extraction by an oscillating water column (OWC) device. The method is based on a mixed-Eulerian-Lagrangian formulation. We examine the effects of the relative draught on the efficiency of 2D OWC energy converters. The oscillating air pressure inside the OWC chamber is modeled by assuming that the air is incompressible and the air-turbine mass-flow rate is proportional to the pressure difference (a linear turbine). For shallow draughts the numerical results agree well with available analytical results. The wave-excited seiching inside the extraction chamber is discussed and the variation of extraction efficiency with dimensionless air-chamber width for different immersion depths is reported.

Numerical study of nonlinear Peregrine breather under finite water depth

2015 ◽  
Vol 108 ◽  
pp. 70-80 ◽  
Author(s):  
Zhe Hu ◽  
Hongxiang Xue ◽  
Wenyong Tang ◽  
Xiaoying Zhang
Keyword(s):  
Water Depth ◽  
Numerical Study ◽  
Finite Water Depth ◽  
Peregrine Breather

scholarly journals Focusing wave group on a current of finite depth

2013 ◽  
Vol 13 (11) ◽  
pp. 2941-2949 ◽  
Author(s):  
D. Merkoune ◽  
J. Touboul ◽  
N. Abcha ◽  
D. Mouazé ◽  
A. Ezersky
Keyword(s):  
Numerical Simulations ◽  
Water Depth ◽  
Focal Point ◽  
Wave Train ◽  
Finite Depth ◽  
Freak Waves ◽  
Finite Water Depth ◽  
Wave Maker ◽  
A Current ◽  
Good Agreement

Abstract. Formation of freak waves resulting from the wave packets propagating in finite water depth on the background of a current is studied experimentally and numerically. In the experiment, the freak waves appear as a result of dispersion focusing of wave train excited by wave maker with modulated frequency. The space evolution of the frequency modulated train is studied in numerical simulations. We showed that in the water of finite depth, a distance of focusing increases and amplitude in the focal point decreases in comparison with infinite water depth. Experimental results are in good agreement with numerical simulations if wave breaking of surface waves does not occur.

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