Error analysis of reconstructed wave force on a circular cylinder by using wave elevation data

2020 ◽  
Vol 209 ◽  
pp. 107311
Author(s):  
Jiabin Liu ◽  
Qinghe Fang ◽  
Anxin Guo ◽  
Hui Li
Keyword(s):  
Circular Cylinder ◽  
Error Analysis ◽  
Wave Force ◽  
Wave Elevation ◽  
Elevation Data ◽  
Reconstructed Wave

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

Development and Assessment of a Nonlinear Wave Prediction Methodology for Surface Vessels

2000 ◽  
Vol 44 (02) ◽  
pp. 96-107
Author(s):  
Donald C. Wyatt
Keyword(s):  
Nonlinear Wave ◽  
Solution Procedure ◽  
Boundary Integral ◽  
Dimensional Solution ◽  
Hull Form ◽  
Ship Waves ◽  
Model Scale ◽  
Wave Elevation ◽  
Elevation Data ◽  
Surface Combatant

A numerical method for the prediction of steady nonlinear ship waves and their dependence on hull geometry is developed and assessed. The method employs desingularized Rankine singularities and Havelock singularities in an iterative boundary-integral solution procedure. The Fortran code incorporating this methodology, Das Boot, is tested on three validation cases and applied to a surface combatant hull form. Nonlinear wave elevation predictions for the case of a moving pressure pulse show a 0.988 correlation with a validated fifth-order spectral prediction. Nonlinear wave elevation predictions for a Series 60 hull form show a 0.974 correlation with model-scale wave elevation data. A nonlinear transom stern boundary condition is implemented. Stern wave predictions employing this model are shown to agree with an analytic two-dimensional solution. Initial predictions for a naval surface combatant incorporating a transom stern geometry show encouraging correlation, 0.81, with model-scale tank test data.

scholarly journals Relative height error analysis of TanDEM-X elevation data

2012 ◽  
Vol 73 ◽  
pp. 30-38 ◽  
Author(s):  
Paola Rizzoli ◽  
Benjamin Bräutigam ◽  
Thomas Kraus ◽  
Michele Martone ◽  
Gerhard Krieger
Keyword(s):  
Error Analysis ◽  
Relative Height ◽  
Elevation Data

Analysis of Wave Loads on Pile-Group Foundation

2013 ◽  
Vol 680 ◽  
pp. 217-221 ◽  
Author(s):  
Yi Min Liu
Keyword(s):  
Circular Cylinder ◽  
Incident Wave ◽  
Pile Foundation ◽  
Pile Group ◽  
Wave Force ◽  
Wave Number ◽  
Back Side ◽  
Wave Loads ◽  
Pile Groups ◽  
Diffraction Wave

The grouping pile foundation is widely used in the construction of bridge over sea and its scale of construction is generally dominated by the wave force on the pile groups. Because of the presence of the slab, not only the incident wave but also the diffraction wave should be considered in calculating wave loads on pile groups. The diffraction from a submerged circular cylinder representing the slab was taken as an example, and wave loads on piles in the diffraction wave field were calculated by using Morison formula. Results show that the effect of slab decreases with the increase of incident wave number. Changing laws of different piles in the pile-group foundation varied with the submerged depth. Wave loads at the meeting-wave side of slab is larger than the back side of that. And the presence of slab caused the deflexion of inline force. The grouping piles coefficient can be taken as 0.7.

Real Time Prediction of Second Order Wave Drift Forces for Wave Force Feed Forward in DP

2010 ◽  
Author(s):  
P. Naaijen ◽  
R. H. M. Huijsmans
Keyword(s):  
Wave Field ◽  
Prediction Error ◽  
Wave Force ◽  
Second Order ◽  
First Order ◽  
Wave Drift ◽  
Wave Elevation ◽  
X Band ◽  
Wave Drift Forces ◽  
Drift Forces

The presented research is an extension of the development of an onboard wave and motion estimation system that aims to predict wave elevation and wave frequent vessel motions some 60–120 s ahead, using remote measurements of short crested waves. The main aim is to provide decision support during motion critical offshore operations. As an addition to this, an attempt is made to predict second order wave drift forces. This can be useful for condition monitoring of a Dynamic Positioning (DP) system [18] or for feed forward of wave drift forces into the control of DP systems. The paper describes the techniques used to predict second order wave drift forces real time from remote wave measurements. For validation, measurement data is used from model experiments during which wave elevation in irregular short crested seas was recorded by a large number of probes simultaneously. A method is described to obtain a 3D representation of a wave field in such a way that it can be used to predict both first order waves and motions and second order forces. The second order forces resulting from the wave field description as obtained from remote probe measurements can be compared to those that have been derived from the probes in the proximity of the prediction location, thus providing insight in the sensitivity of the 2nd order wave force prediction error with respect to the first order wave prediction error. In a full scale field situation, remote wave sensing can be provided by X-band radar. Possibilities for application of the developed method with the WAMOS II X-band radar system is considered.

Data Mining Pt. Reyes Buoy for Rare Wave Groups

2015 ◽  
Author(s):  
Harleigh C. Seyffert ◽  
Armin W. Troesch
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
University Of California ◽  
Series Data ◽  
Wave Groups ◽  
Naturally Occurring ◽  
Wave Elevation ◽  
Information Program ◽  
Elevation Data ◽  
Definition Of

This paper addresses the existence of rare wave groups, as defined by Kim and Troesch [1], by examining time series data from the Pt. Reyes buoy. The buoy is operated by the Coastal Data Information Program (CDIP), University of California San Diego. The definition of rare wave groups [1] used in this paper differs from the more commonly used wave group definition based on threshold crossings. With the time series data from the Pt. Reyes buoy, these rare wave groups are shown to be a naturally occurring phenomenon. The nature of the data is examined, as well as the analysis methods and findings. By sifting through 17 years of wave elevation data from the Pt. Reyes buoy, this preliminary work addresses not only the question to what extent rare wave groups exist in nature, but also, what their probability of occurrence is.

scholarly journals Interaction of a Solitary Wave with Vertical Fully/Partially Submerged Circular Cylinders with/without a Hollow Zone

2020 ◽  
Vol 8 (12) ◽  
pp. 1022
Author(s):  
Chih-Hua Chang
Keyword(s):  
Circular Cylinder ◽  
Solitary Wave ◽  
Three Dimensional ◽  
Vertical Cylinder ◽  
Wave Model ◽  
Circular Cylinders ◽  
Cylinder Surface ◽  
Wave Elevation ◽  
Curvilinear Grid ◽  
Nonlinear Potential

In this article, a three-dimensional, fully nonlinear potential wave model is applied based on a curvilinear grid system. This model calculates the wave action on a fully/partially submerged vertical cylinder with or without a hollow zone. As basic verification, a solitary wave hitting a single fully or partially submerged circular cylinder is tested, and our numerical results agree with the experimental results obtained by others. The influence of cylinder immersion depth and size on the wave elevation change on the cylinder surface is considered. The model is also applied to investigate the wave energy of a solitary wave passing through a hollow circular cylinder to determine the effect of the size and draft on the wave oscillating in the hollow zone.

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.

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