Second-order wave run-up on a vertical cylinder adjacent to a plane wall based on the application of quadratic transfer function in bi-directional waves

2021 ◽  
Vol 76 ◽  
pp. 102879
Author(s):  
Peiwen Cong ◽  
Bin Teng ◽  
Wei Bai
Keyword(s):  
Transfer Function ◽  
Vertical Cylinder ◽  
Second Order ◽  
Plane Wall ◽  
Directional Waves ◽  
Run Up

The complete second-order diffraction solution for an axisymmetric body Part 1. Monochromatic incident waves

1989 ◽  
Vol 200 ◽  
pp. 235-264 ◽  
Author(s):  
Moo-Hyun Kim ◽  
Dick K. P. Yue
Keyword(s):  
Free Surface ◽  
Vertical Cylinder ◽  
Body Part ◽  
Axisymmetric Body ◽  
Second Order ◽  
The Body ◽  
Surface Integral ◽  
Analytic Integration ◽  
Local Wave ◽  
Run Up

We study the diffraction, to second order, of plane monochromatic incident gravity waves by a vertically axisymmetric body. The second-order double-frequency diffraction potential is obtained explicitly. A sequence of one-dimensional integral equations along the generator of the body involving free-surface ring sources of general order are formulated and solved for the circumferential components of the second-order potential. The solution is expedited by analytic integration in the entire local-wave-free outer field of a requisite free-surface integral. The method is validated by extensive convergence tests and comparisons to semi-analytic results for the second-order forces and moments on a uniform vertical circular cylinder. Complete second-order forces, moments, surface pressures and run-up on the vertical cylinder as well as a truncated vertical cone are presented. A summary of the important findings is given in §5.

Analysis of the First Order and Slowly Varying Motions of an Axisymmetric Floating Body in Bichromatic Waves

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
João Pessoa ◽  
Nuno Fonseca ◽  
C. Guedes Soares
Keyword(s):  
Vertical Cylinder ◽  
Vertical Axis ◽  
Second Order ◽  
The Body ◽  
Floating Body ◽  
Drift Motion ◽  
First Order ◽  
Motion Responses ◽  
Simple Geometry ◽  
Good Agreement

The paper presents an experimental and numerical investigation on the motions of a floating body of simple geometry subjected to harmonic and biharmonic waves. The experiments were carried out in three different water depths representing shallow and deep water. The body is axisymmetric about the vertical axis, like a vertical cylinder with a rounded bottom, and it is kept in place with a soft mooring system. The experimental results include the first order motion responses, the steady drift motion offset in regular waves and the slowly varying motions due to second order interaction in biharmonic waves. The hydrodynamic problem is solved numerically with a second order boundary element method. The results show a good agreement of the numerical calculations with the experiments.

Drift Forces on a Floating Body of Simple Geometry Due to Second Order Interactions Between Pairs of Harmonics With Different Frequencies

2009 ◽  
Author(s):  
Joa˜o Pessoa ◽  
Nuno Fonseca ◽  
C. Guedes Soares
Keyword(s):  
Vertical Cylinder ◽  
Vertical Axis ◽  
Second Order ◽  
The Body ◽  
Floating Body ◽  
Order Problem ◽  
Simple Geometry ◽  
The Mean ◽  
Order Quantities ◽  
Drift Forces

The paper presents an investigation of the slowly varying second order drift forces on a floating body of simple geometry. The body is axis-symmetric about the vertical axis, like a vertical cylinder with a rounded bottom and a ratio of diameter to draft of 3.25. The hydrodynamic problem is solved with a second order boundary element method. The second order problem is due to interactions between pairs of incident harmonic waves with different frequencies, therefore the calculations are carried out for several difference frequencies with the mean frequency covering the whole frequency range of interest. Results include the surge drift force and pitch drift moment. The results are presented in several stages in order to assess the influence of different phenomena contributing to the global second order responses. Firstly the body is restrained and secondly it is free to move at the wave frequency. The second order results include the contribution associated with quadratic products of first order quantities, the total second order force, and the contribution associated to the free surface forcing.

The Effect of Springing Response of a TLP on Tether Fatigue

1996 ◽  
Vol 118 (3) ◽  
pp. 169-173
Author(s):  
A. Naess
Keyword(s):  
Transfer Function ◽  
Fatigue Damage ◽  
Second Order ◽  
Sum Frequency ◽  
Engineering Approach ◽  
Computer Codes

The purpose of this paper is to investigate the effect on estimated fatigue damage of TLP tethers of the method used to model the springing response. In particular, the goal has been to look into the consequence for long-term fatigue calculation of modeling the springing response as a second-order, sum-frequency process as opposed to assuming that the springing response is Gaussian. It is shown that with a standard engineering approach to the calculation of long-term fatigue damage, this effect is in fact marginal. However, the deviation between the numerical estimates of the quadratic transfer function describing the springing response as provided by different computer codes is found to produce estimates of the long-term fatigue that exhibit substantial variability.

scholarly journals Research on Heat Transfer Dynamic Characteristics of Composite Layer Based on Laplace Transform

2019 ◽  
Author(s):  
Chunyu Xu ◽  
Junhua Lin ◽  
Wenhao Liu ◽  
Yuanbiao Zhang
Keyword(s):  
Heat Transfer ◽  
Composite Materials ◽  
Temperature Distribution ◽  
Transfer Function ◽  
Dynamic Characteristics ◽  
Transfer Functions ◽  
Composite Layer ◽  
Engineering Application ◽  
Second Order ◽  
Inverse Transformation

This paper predict and effectively control the temperature distribution of the steady-state and transient states of anisotropic four-layer composite materials online, knowing the density, specific heat, heat conductivity and thickness of the composite materials. Based on the transfer function, a mathematical model was established to study the dynamic characteristics of heat transfer of the composite materials. First of all, the Fourier heat transfer law was used to establish a one-dimensional Fourier heat conduction differential equation for each composite layer, and the Laplace transformation was carried out to obtain the system function. Then the approximate second-order transfer function of the system was obtained by Taylor expansion, and the Laplace inverse transformation was carried out to obtain the transfer function of the whole system in the time domain. Finally, the accuracy of the simplified analytical solutions of the first, second and third order approximate transfer functions was compared with computer simulation. The results showed that the second order approximate transfer functions can describe the dynamic process of heat transfer better than others. The research on the dynamic characteristics of heat transfer in the composite layer and the dynamic model of heat transfer in composite layer proposed in this paper have a reference value for practical engineering application. It can effectively predict the temperature distribution of composite layer material and reduce the cost of experimental measurement of heat transfer performance of materials.

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