Wave Forces Acting on a Moving Cylinder

1988 ◽  
Vol 110 (4) ◽  
pp. 315-319 ◽  
Author(s):  
W. Koterayama ◽  
M. Nakamura
Keyword(s):  
Circular Cylinder ◽  
Phase Difference ◽  
Relative Motion ◽  
Wave Force ◽  
Added Mass ◽  
Wave Forces ◽  
Force Measurements ◽  
Regular Waves ◽  
Moving Cylinder ◽  
Fixed Cylinder

Wave forces acting on a surging circular cylinder in regular waves are measured in a wave tank. Experiments are carried on various combinations of the amplitude of a wave and a surge, and the phase difference between them. The results of experiments are compared with those of calculations. The Morison equation extended to the case of relative motion is employed to calculate the forces on the cylinder. The inertia, added mass and drag coefficients used in the calculations are obtained from wave force measurements on a fixed cylinder and forced-surge tests in still water.

Nonlinear wave forces on a circular cylinder

1989 ◽  
Vol 16 (2) ◽  
pp. 182-187 ◽  
Author(s):  
Michael Isaacson ◽  
Qi-Hua Zuo
Keyword(s):  
Circular Cylinder ◽  
Nonlinear Wave ◽  
Perturbation Methods ◽  
Wave Force ◽  
Offshore Structures ◽  
Wave Forces ◽  
Ocean Engineering ◽  
Time Stepping ◽  
Wave Effects ◽  
Accuracy And Stability

Nonlinear wave forces on a surface-piercing vertical circular cylinder are considered using a time-stepping method previously developed which is based on Green's theorem. Possible improvements in the efficiency, accuracy, and stability of the method are considered. Results based on this method are compared with those obtained previously using perturbation methods as well as with experimental results. It is found that the time-stepping method adopted here is quite reasonable. Wave force coefficients are given as functions of the governing parameters of the problem and the importance of nonlinear wave effects on the forces is assessed. Key words: hydrodynamics, ocean engineering, offshore structures, waves, wave forces.

Computational Fluid Dynamics Simulations of Regular and Irregular Waves Past a Horizontal Semi-Submerged Cylinder

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Shengnan Liu ◽  
Muk Chen Ong ◽  
Charlotte Obhrai ◽  
Sopheak Seng
Keyword(s):  
Free Surface ◽  
Numerical Simulations ◽  
Wave Height ◽  
Stokes Equations ◽  
Wave Force ◽  
Numerical Results ◽  
Irregular Waves ◽  
Wave Forces ◽  
Regular Waves ◽  
Peak Period

Two-dimensional (2D) numerical simulations have been performed to investigate both regular and irregular waves past a fixed horizontally semisubmerged circular cylinder. The 2D simulations are carried out by solving Navier–Stokes equations discretized by finite volume method. Volume of fluid (VOF) method is employed to capture the free surface in the numerical wave tank (NWT). Validation studies have been performed by comparing the numerical results of free surface waves past the cylinder with the published experimental and numerical data. The present numerical results are in good agreement with both the experimental and the other numerical results in terms of hydrodynamic forces and free surface elevation. Subsequently, the effects of the wave height and the wavelength on wave–structure interaction are investigated by conducting numerical simulations on the regular and the irregular waves past a semisubmerged cylinder at different wave heights and the wavelengths. The averaged and maximum vertical wave forces on the cylinder increase with the increasing wave height. The numerical results for the irregular waves are compared with those induced by the regular waves in terms of the maximum and averaged vertical wave forces. When the significant wave height and the spectral peak period of the irregular waves are equal to the wave height and the wave period of the regular waves, the maximum vertical wave force induced by the irregular waves is larger than that induced by the regular waves, meanwhile, the average vertical wave forces have the contrary relationship.

Wave Loads on a Perforated Circular Caisson and Suction Pipe of a Sea Water Intake Structure

2004 ◽  
Author(s):  
K. Vijayalakshmi ◽  
S. Neelamani ◽  
R. Sundaravadivelu
Keyword(s):  
Sea Water ◽  
Wave Force ◽  
Wave Forces ◽  
Wave Loads ◽  
Regular Waves ◽  
Suction Pipe ◽  
Well Model ◽  
Surface Fluctuations ◽  
Run Up ◽  
Intake Structure

The wave force on a seawater intake well model consisting of a perforated circular caisson (500mm diameter) encircling a vertical suction pipe (50mm dia) is measured experimentally. The effect of porosity of the caisson wall, incident wave height and wave period on the in-line forces on the caisson and suction pipe is investigated. The porosity of the caisson was varied from 4.54% to 19.15%. Waves of wide ranges of heights and periods were used. The wave forces on the outer caisson & inner cylinder, water surface fluctuations in the interior & exterior of the caisson and wave run-up on the outer caisson & inner cylinder are studied. The present paper includes the wave forces on the outer perforated circular caisson and inner circular cylinder due to regular waves only.

scholarly journals SIMULATION OF WAVE FORCES ON A HORIZONTAL CYLINDER

1988 ◽  
Vol 1 (21) ◽  
pp. 163
Author(s):  
Susumu Tsuzuki ◽  
Kiyoshi Horikawa ◽  
Akira Watanabe
Keyword(s):  
Circular Cylinder ◽  
Laboratory Data ◽  
Vortex Method ◽  
Wave Force ◽  
Horizontal Cylinder ◽  
Wave Forces ◽  
Discrete Vortex ◽  
Discrete Vortex Method ◽  
Experimental Findings ◽  
Horizontal Circular Cylinder

The characteristics of wave forces acting on a horizontal circular cylinder were investigated through numerical calculations as well as experimental findings. The laboratory data on wave forces were analyzed by the concept of wave force path and classified into two types. One is the circular type and the other one is the 8 - shaped type. In order to analyze the above phenomena, the discrete vortex method was applied with appropriate assumptions. The comparison between the numerically calculated results and laboratory data shows that the simulation model proposed in this paper seems to be favorable to predict the wave forces acting on a horizontal circular cylinder within a certain range of conditions.

Note on a paper by Ogilvie: the interaction between waves and a submerged horizontal cylinder

1999 ◽  
Vol 394 ◽  
pp. 355-356 ◽  
Author(s):  
F. ARENA
Keyword(s):  
Circular Cylinder ◽  
Pressure Distribution ◽  
Gravity Waves ◽  
Deep Water ◽  
Velocity Potential ◽  
Horizontal Cylinder ◽  
Moving Cylinder ◽  
Time Periodic ◽  
Fixed Cylinder ◽  
Periodic Space

Ogilvie (1963) obtained the solution for the interaction between gravity waves and a horizontal submerged circular cylinder on deep water. It is shown herein that in this solution the expressions for the velocity potential (both for the moving cylinder and for the fixed cylinder) lack one term: a time-periodic space-independent term, which does not modify the load, but has some important consequence on the pressure distribution.

scholarly journals NONLINEAR METHOD FOR REAL-TIME WAVE FORCE RECONSTRUCTION ON A CYLINDER BY USING MEASURED WAVE ELEVATION

2020 ◽  
pp. 6
Author(s):  
Jiabin Liu ◽  
Anxin Guo
Keyword(s):  
Circular Cylinder ◽  
Real Time ◽  
Linear Method ◽  
Wave Force ◽  
Wave Forces ◽  
Frequency Wave ◽  
Wave Fields ◽  
Wave Elevation ◽  
Force Reconstruction ◽  
Incident Waves

For a constructed offshore structure, wave force evaluation on its foundation in an intricate wave field will benefit the load data collection and structural safety monitoring. Then, the collected data can provide valuable references for similar structures constructed in the same ocean region in the future. A real-time wave force prediction can further contribute to the active control of the structural dynamic responses. According to the incident waves known or unknown, the wave force reconstruction issue can be divided into two categories. When the incident waves are known, the wave forces on the cylinder can be achieved by the theoretical methods or numerical methods. When the incident waves are unknown, researchers try to reconstruct the wave force indirectly. For a small-scale cylinder, researchers predicted the wave forces by using the Morison equation in random wave fields with measured data of wave elevation. These studies indicated a shortcut for determining the wave force on the cylinder by using the data of water surface elevation. However, the wave fields are assumed to be undisturbed by the structure in the mentioned studies. For a vertical larger-scale cylinder, Liu et al. (2018) established a prediction method to reconstruct wave force by using the recorded data of wave elevation around the cylinder. A linear method for the circular cylinder is provided that shows an excellent reconstruction of wave force for its dominant frequent components. However, reconstruction results showed that high frequency wave forces are underestimated and low frequency wave forces are overestimated, which means the linear method is incapable to predict the nonlinear wave forces on the structure. An improved method is built for reconstructing wave forces on a circular cylinder in the real-time. Two different algorithms, Fast Fourier Translation (FFT) and Recursive Least Squares (RLS), for real-time reconstruction are conducted. The present method can be applied for the data collection of wave loads on a constructed offshore structure.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/PYOuCNP8pgQ

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 Characteristics of Breaking Wave Forces on Piles over a Permeable Seabed

2021 ◽  
Vol 9 (5) ◽  
pp. 520
Author(s):  
Zhenyu Liu ◽  
Zhen Guo ◽  
Yuzhe Dou ◽  
Fanyu Zeng
Keyword(s):  
Wave Breaking ◽  
Stokes Equations ◽  
Slope Angle ◽  
Wave Force ◽  
Breaking Waves ◽  
Offshore Wind ◽  
Secondary Wave ◽  
Wave Forces ◽  
Breaking Wave ◽  
Breaking Wave Forces

Most offshore wind turbines are installed in shallow water and exposed to breaking waves. Previous numerical studies focusing on breaking wave forces generally ignored the seabed permeability. In this paper, a numerical model based on Volume-Averaged Reynolds Averaged Navier–Stokes equations (VARANS) is employed to reveal the process of a solitary wave interacting with a rigid pile over a permeable slope. Through applying the Forchheimer saturated drag equation, effects of seabed permeability on fluid motions are simulated. The reliability of the present model is verified by comparisons between experimentally obtained data and the numerical results. Further, 190 cases are simulated and the effects of different parameters on breaking wave forces on the pile are studied systematically. Results indicate that over a permeable seabed, the maximum breaking wave forces can occur not only when waves break just before the pile, but also when a “secondary wave wall” slams against the pile, after wave breaking. With the initial wave height increasing, breaking wave forces will increase, but the growth can decrease as the slope angle and permeability increase. For inclined piles around the wave breaking point, the maximum breaking wave force usually occurs with an inclination angle of α = −22.5° or 0°.

scholarly journals Added mass of a circular cylinder oscillating in a free stream

2013 ◽  
Vol 469 (2156) ◽  
pp. 20130135 ◽  
Author(s):  
Efstathios Konstantinidis
Keyword(s):  
Circular Cylinder ◽  
Free Stream ◽  
Transverse Velocity ◽  
Inertial Force ◽  
Added Mass ◽  
Stream Velocity ◽  
Virtual Experiment ◽  
Classical Formulation ◽  
Fundamental Understanding ◽  
Two Dimensional Flow

The fundamental understanding of the added mass phenomenon associated with the motion of a solid body relative to a fluid is revisited. This paper focuses on the two-dimensional flow around a circular cylinder oscillating transversely in a free stream. A virtual experiment reveals that the classical approach to this problem leads to a paradox. The inertial force is derived afresh based on analysis of the motion in a frame of reference attached to the cylinder centroid, which overcomes the paradox in the classical formulation. It is shown that the inertial force depends not only on the acceleration of the cylinder per se , but also on the relative motion between body and fluid embodied in a parameter called alpha, α , which represents the ratio of the maximum transverse velocity of the cylinder to the free-stream velocity; the induced inertial force is directionally varying and non-harmonic in time depended on the alpha parameter. It is further shown that the component of the inertial force in the transverse direction is negligible for α <0.1, increases quadratically for α <0.5, and tends asymptotically to the classical result as , i.e. in still fluid.

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