scholarly journals Wave Exciting Forces on Groups of Floating Bodies

1979 ◽  
Vol 1979 (145) ◽  
pp. 79-87 ◽  
Author(s):  
Akira Masumoto ◽  
Yoshio Yamagami ◽  
Ryuji Sakata
Keyword(s):  
Floating Bodies ◽  
Exciting Forces ◽  
Wave Exciting Forces

scholarly journals Wave forces on three-dimensional floating bodies with small forward speed

1991 ◽  
Vol 227 ◽  
pp. 135-160 ◽  
Author(s):  
Jan Nossen ◽  
John Grue ◽  
Enok Palm
Keyword(s):  
Velocity Potential ◽  
The Body ◽  
Wave Forces ◽  
Forward Speed ◽  
Floating Bodies ◽  
Wave Drift ◽  
Exciting Forces ◽  
Wave Exciting Forces ◽  
Wave Drift Damping ◽  
The Mean

A boundary-integral method is developed for computing first-order and mean second-order wave forces on floating bodies with small forward speed in three dimensions. The method is based on applying Green's theorem and linearizing the Green function and velocity potential in the forward speed. The velocity potential on the wetted body surface is then given as the solution of two sets of integral equations with unknowns only on the body. The equations contain no water-line integral, and the free-surface integral decays rapidly. The Timman-Newman symmetry relations for the added mass and damping coefficients are extended to the case when the double-body flow around the body is included in the free-surface condition. The linear wave exciting forces are found both by pressure integration and by a generalized far-field form of the Haskind relations. The mean drift force is found by far-field analysis. All the derivations are made for an arbitrary wave heading. A boundary-element program utilizing the new method has been developed. Numerical results and convergence tests are presented for several body geometries. It is found that the wave exciting forces and the mean drift forces are most influenced by a small forward speed. Values of the wave drift damping coefficient are computed. It is found that interference phenomena may lead to negative wave drift damping for bodies of complicated shape.

Computation of Hydrodynamic Interaction of Multiple Bodies in Waves With a Panel-Free Method

2005 ◽  
Author(s):  
Wei Qiu ◽  
Hongxuan Peng ◽  
Sander M. Calisal ◽  
Jianhong Wang
Keyword(s):  
Hydrodynamic Interaction ◽  
Gaussian Quadrature ◽  
Time Domain Analysis ◽  
Performance Study ◽  
Floating Bodies ◽  
B Splines ◽  
Exciting Forces ◽  
Wave Exciting Forces ◽  
The Green Function ◽  
The Time Domain

The hydrodynamic interaction of multiple floating bodies in waves has been computed in the frequency domain based on the panel-free method developed earlier for the time-domain analysis. The integral equations are first desingularized by removing the singularity in the Green function and then discretized by Gaussian quadrature over the exact geometry. Non-uniform rational B-splines (NURBS) surfaces are employed to represent the exact body surface. Robustness and accuracy of the method has been demonstrated by its application to vertically floating cylinders. Computed motions, hydrodynamic coefficients and wave exciting forces due to interactions are presented and compared with other published results. The numerical method has also been applied to the performance study of a wave energy converter. The computed results were compared with the experimental ones.

Theory of Short Wave Excitation

1986 ◽  
Vol 30 (03) ◽  
pp. 147-152
Author(s):  
Yong Kwun Chung
Keyword(s):  
Incident Wave ◽  
Characteristic Length ◽  
Finite Depth ◽  
Short Wave ◽  
The Body ◽  
Wave Number ◽  
Floating Body ◽  
Wave Excitation ◽  
Exciting Forces ◽  
Wave Exciting Forces

When the wavelength of the incident wave is short, the total surface potential on a floating body is found to be 2∅ i & O (m-l∅ i) on the lit surface and O (m-l∅ j) on the shadow surface where ~b i is the potential of the incident wave and m the wave number in water of finite depth. The present approximation for wave exciting forces and moments is reasonably good up to X/L ∅ 1 where h is the wavelength and L the characteristic length of the body.

Experimental Investigation of the First and Second Order Wave Exciting Forces on a Restrained Body in Long Crested Irregular Waves

2011 ◽  
Author(s):  
Joa˜o Pessoa ◽  
Nuno Fonseca ◽  
Suresh Rajendran ◽  
C. Guedes Soares
Keyword(s):  
Experimental Investigation ◽  
Transfer Functions ◽  
Vertical Cylinder ◽  
Vertical Axis ◽  
Second Order ◽  
The Body ◽  
Irregular Waves ◽  
Numerical Predictions ◽  
Exciting Forces ◽  
Wave Exciting Forces

The paper presents an experimental investigation of the first order and second order wave exciting forces acting on a body of simple geometry subjected to long crested irregular waves. The body is axis-symmetric about the vertical axis, like a vertical cylinder with a rounded bottom, and it is restrained from moving. Second order spectral analysis is applied to obtain the linear spectra, coherence spectra and cross bi-spectra of both the incident wave elevation and of the horizontal and vertical wave exciting forces. Then the linear and quadratic transfer functions (QTF) of the exciting forces are obtained. The QTF obtained from the analysis of irregular wave measurements are compared with results from experiments in bi-chromatic waves and with numerical predictions from a second order potential flow code.

A Numerical Study on Hydrodynamic Interactions Between Large Numbers of Multiple Floating Bodies

2003 ◽  
Author(s):  
Yoshiyuki Inoue ◽  
Mir Tareque Ali
Keyword(s):  
Numerical Study ◽  
Computer Code ◽  
Hydrodynamic Forces ◽  
Hydrodynamic Interactions ◽  
Physical Aspect ◽  
Floating Bodies ◽  
Coupled Equations ◽  
Large Numbers ◽  
Exciting Forces ◽  
Multi Body

This paper investigates the hydrodynamic interactions between large numbers of multiple bodies floating in each other’s close vicinity. The physical aspect of hydrodynamic interaction is rather complicated and numerically sound scheme is highly recommended to study this complex phenomenon. In the present study, the 3D sink-source method has been adopted to determine the hydrodynamic forces by taking into account the effect of hydrodynamic interactions among the different floating bodies, and the coupled equations of motions are solved directly. The validation of the computer code developed for this purpose has been justified by comparing the present results with that of the published ones for simple geometrical shaped floating bodies. The numerical computations have been carried out for different numbers of various freely floating multi-body systems and the hydrodynamic interactions between the floating bodies have been studied by calculating the hydrodynamic forces, first order wave exciting forces and motion responses. Finally some conclusions have been drawn on the basis of the present analysis.

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