Water Waves and Marine Structure Interaction

2004 ◽  
Author(s):  
Octavi Sado´ Garriga ◽  
Jeffrey M. Falzarano
Keyword(s):  
Free Surface ◽  
New Orleans ◽  
Water Waves ◽  
Frequency Estimation ◽  
Experimental Results ◽  
Oscillating Water Column ◽  
Towing Tank ◽  
Structure Interaction ◽  
Marine Structure ◽  
The University

The purpose of this paper is to combine and extend existing potential flow theory in order to analyze the linear free surface problem of an Oscillating Water Column (OWC) device and apply it to moonpool design. Analytical results were obtained implementing the previously derived theories, and later compared to experimental results conducted at the University of New Orleans Towing Tank. The model tests consisted of a study of a cylindrical OWC. The theoretical and experimental results of the free surface for the OWC tests agree for the resonant frequency estimation response but they disagree on the amplitude of the response.

Water Wave Interaction on a Truncated Vertical Cylinder

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Octavi Sadó Garriga ◽  
Jeffrey M. Falzarano
Keyword(s):  
Free Surface ◽  
New Orleans ◽  
Frequency Estimation ◽  
Vertical Cylinder ◽  
Wave Interaction ◽  
Experimental Results ◽  
Oscillating Water Column ◽  
Towing Tank ◽  
The University ◽  
Moon Pool

The purpose of this paper is to combine and extend existing potential flow theory in order to analyze the linear free surface problem of an oscillating water column (OWC) device and apply it to moon pool design. Analytical results were obtained implementing the previously derived theories, and later compared to experimental results conducted at the University of New Orleans Towing Tank. The model tests consisted of a study of a cylindrical OWC. The theoretical and experimental results of the free surface for the OWC tests agree for the resonant frequency estimation response but they disagree on the amplitude of the response.

Design of the University of New Orleans Ship-Offshore University Laboratory for Offshore Industry Support

1988 ◽  
Vol 110 (3) ◽  
pp. 133-140 ◽  
Author(s):  
R. Latorre
Keyword(s):  
New Orleans ◽  
Water Current ◽  
Offshore Structure ◽  
Water Research ◽  
Towing Tank ◽  
Calm Water ◽  
Tank Design ◽  
Offshore Industry ◽  
The University ◽  
University Laboratory

On July 23, 1987, the University of New Orleans (UNO) dedicated its new Engineering Building, which houses a 38.3 m×4.57 m×0–2.134 m deep ship-offshore university laboratory tow tank. This paper covers the initial stages of the project and summarizes the towing tank design for ship-offshore testing. The tank is configured for three purposes: 1) conventional ship research in deep water with calm water or waves; 2) offshore structure testing with provision for observation and anchoring; 3) shallow water research in calm water, current, and waves.

Numerical Simulation of Dynamic Response of Structure Caused by Wave Impact Pressure Using an Eulerian Scheme With Lagrangian Particles

2009 ◽  
Author(s):  
Hidemi Mutsuda ◽  
Yasuaki Doi
Keyword(s):  
Free Surface ◽  
Elastic Deformation ◽  
Wave Breaking ◽  
Fluid Structure Interaction ◽  
Experimental Results ◽  
Impact Pressure ◽  
Wave Impact ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Lagrangian Particles

This study focuses on the development of computational techniques for computing fluid-structure interaction with wave breaking. This is of practical relevance in both ocean, and ship hydrodynamics. This paper also presents a prediction of the local highly pressure load impacting on a rigid and elastic structure caused by fluid force including impact pressure. We have developed a new numerical scheme that combines a Eulerian scheme with Lagrangian particles, i.e. free surface particles and SPH particles, to compute fluid-structure interaction caused by impact pressure. In this model, we employed two kinds of particles. One is free surface particle located near the free surface to capture air-water interface accurately. The other one is SPH particle to compute solid motion and elastic deformation. The air-water mixing flow is treated on a fixed Eulerian grid with the free surface particles to rebuild the density function for capturing the interface in filamentary regions that are under-resolved. Conversely, the structure is solved using the particle method, SPH. These Lagrangian particles are useful and available to capture the interface between different phases. In this paper, the proposed method was applied to the water entry problems of a V-shaped wedge, a horizontal flat-plate, a circular cylinder, an elastic cylindrical shell and impact pressure acting on an elastic wall caused by wave breaking. The free surface and elastic deformation are compared with both numerical and experimental results. The pressure and strain predictions are also compared with experimental results obtained by other researchers.

scholarly journals A Synopsis Based Approach for Itemset Frequency Estimation over Massive Multi-Transaction Stream

2021 ◽  
Vol 16 (2) ◽  
pp. 1-30
Author(s):  
Guangtao Wang ◽  
Gao Cong ◽  
Ying Zhang ◽  
Zhen Hai ◽  
Jieping Ye
Keyword(s):  
Frequency Estimation ◽  
Frequent Itemsets ◽  
Frequent Itemset ◽  
Experimental Results ◽  
Closure Property ◽  
Frequent Itemset Mining ◽  
Itemset Mining ◽  
Minimum Value ◽  
Downward Closure ◽  
Bounded Size

The streams where multiple transactions are associated with the same key are prevalent in practice, e.g., a customer has multiple shopping records arriving at different time. Itemset frequency estimation on such streams is very challenging since sampling based methods, such as the popularly used reservoir sampling, cannot be used. In this article, we propose a novel k -Minimum Value (KMV) synopsis based method to estimate the frequency of itemsets over multi-transaction streams. First, we extract the KMV synopses for each item from the stream. Then, we propose a novel estimator to estimate the frequency of an itemset over the KMV synopses. Comparing to the existing estimator, our method is not only more accurate and efficient to calculate but also follows the downward-closure property. These properties enable the incorporation of our new estimator with existing frequent itemset mining (FIM) algorithm (e.g., FP-Growth) to mine frequent itemsets over multi-transaction streams. To demonstrate this, we implement a KMV synopsis based FIM algorithm by integrating our estimator into existing FIM algorithms, and we prove it is capable of guaranteeing the accuracy of FIM with a bounded size of KMV synopsis. Experimental results on massive streams show our estimator can significantly improve on the accuracy for both estimating itemset frequency and FIM compared to the existing estimators.

scholarly journals An alternative approach to study irrotational periodic gravity water waves

2021 ◽  
Vol 72 (4) ◽  
Author(s):  
Biswajit Basu ◽  
Calin I. Martin
Keyword(s):  
Free Surface ◽  
Water Waves ◽  
Water Wave ◽  
Wave Problem ◽  
Water Wave Problem ◽  
Stagnation Points ◽  
Alternative Approach ◽  
New Formulation ◽  
Bounded Below ◽  
Surface Dynamic

AbstractWe are concerned here with an analysis of the nonlinear irrotational gravity water wave problem with a free surface over a water flow bounded below by a flat bed. We employ a new formulation involving an expression (called flow force) which contains pressure terms, thus having the potential to handle intricate surface dynamic boundary conditions. The proposed formulation neither requires the graph assumption of the free surface nor does require the absence of stagnation points. By way of this alternative approach we prove the existence of a local curve of solutions to the water wave problem with fixed flow force and more relaxed assumptions.

scholarly journals Bound Coherent Structures Propagating on the Free Surface of Deep Water

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 115
Author(s):  
Dmitry Kachulin ◽  
Sergey Dremov ◽  
Alexander Dyachenko
Keyword(s):  
Free Surface ◽  
Deep Water ◽  
Coherent Structures ◽  
Water Waves ◽  
Nonlinear Models ◽  
Ideal Incompressible Fluid ◽  
Equation Model ◽  
System Of Nonlinear Equations ◽  
Potential Flows ◽  
Deep Water Waves

This article presents a study of bound periodically oscillating coherent structures arising on the free surface of deep water. Such structures resemble the well known bi-soliton solution of the nonlinear Schrödinger equation. The research was carried out in the super-compact Dyachenko-Zakharov equation model for unidirectional deep water waves and the full system of nonlinear equations for potential flows of an ideal incompressible fluid written in conformal variables. The special numerical algorithm that includes a damping procedure of radiation and velocity adjusting was used for obtaining such bound structures. The results showed that in both nonlinear models for deep water waves after the damping is turned off, a periodically oscillating bound structure remains on the fluid surface and propagates stably over hundreds of thousands of characteristic wave periods without losing energy.

scholarly journals New exact relations for steady irrotational two-dimensional gravity and capillary surface waves

2017 ◽  
Vol 376 (2111) ◽  
pp. 20170220 ◽  
Author(s):  
Didier Clamond
Keyword(s):  
Free Surface ◽  
Gravity Waves ◽  
Water Waves ◽  
Two Dimensional ◽  
Physical Plane ◽  
Theme Issue ◽  
Nonlinear Water Waves ◽  
Dimensional Gravity ◽  
Irrotational Motion ◽  
Exact Relations

Steady two-dimensional surface capillary–gravity waves in irrotational motion are considered on constant depth. By exploiting the holomorphic properties in the physical plane and introducing some transformations of the boundary conditions at the free surface, new exact relations and equations for the free surface only are derived. In particular, a physical plane counterpart of the Babenko equation is obtained. This article is part of the theme issue ‘Nonlinear water waves’.

Experimental Study of a Tanker Ship Squat in Shallow Water

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Mohammadreza Fathi Kazerooni ◽  
Mohammad Saeed Seif
Keyword(s):  
Experimental Study ◽  
Shallow Water ◽  
Experimental Approach ◽  
Model Tests ◽  
Ship Hull ◽  
Experimental Results ◽  
Shallow Waters ◽  
Towing Tank ◽  
Ship Model

One of the phenomena restricting the tanker navigation in shallow waters is reduction of under keel clearance in the terms of sinkage and dynamic trim that is called squatting. According to the complexity of flow around ship hull, one of the best methods to predict the ship squat is experimental approach based on model tests in the towing tank. In this study model tests for tanker ship model had been held in the towing tank and squat of the model are measured and analyzed. Based on experimental results suitable formulae for prediction of these types of ship squat in fairways are obtained.

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