scholarly journals A Multiphysics Multiscale 3-D Computational Wave Basin Model for Wave Impact Load on a Cylindrical Structure

2009 ◽  
Vol 4 (6) ◽  
pp. 450-461 ◽  
Author(s):  
Solomon C. Yim ◽  
◽  
Wenbin Zhang
Keyword(s):  
Water Surface ◽  
Fluid Structure Interaction ◽  
Surface Elevation ◽  
Horizontal Force ◽  
Wave Impact ◽  
Fluid Structure ◽  
Cylindrical Structure ◽  
Structure Interaction ◽  
Wave Basin ◽  
Overturning Moment

A multiphysics multiscale finite-element based nonlinear computational wave basin (CWB) model is developed using LS-DYNA. Its predictive capability is calibrated using a large-scale fluid-structure interaction experiment conducted in a 3-dimensional wave basin to determine wave impact on a cylindrical structure. This study focuses on evaluating CWB accuracy using two wave excitation conditions — plane and focused solitary waves — and two cylinder arrangements — single and multiple cylinders. Water surface elevation and water particle velocity are predicted numerically for the fluid domain, obtaining horizontal force, overturning moment, and dynamic pressure on the cylindrical structure and calibrated against experimental measurement. The CWB model predicts wave motion characteristics — water surface elevation and velocity, and integrated structural response — horizontal force and overturning moment, for the given wave conditions well. Computation time increases and the predictive accuracy decreases as nonlinear fluid-structure interaction becomes increasingly complex. A study of computation settings for improving computation performance showed that a high-performance parallel-computing hardware platform is needed to model details of highly nonlinear physics of fluid flow including wave breaking and turbulence.

Physical and numerical large-scale wave basin modeling of fluid-structure interaction and wave impact phenomena

2014 ◽  
Vol 9 (1) ◽  
pp. 29-47
Author(s):  
Solomon C. Yim ◽  
Mohsen Azadbakht ◽  
Ravi Challa ◽  
Junhui Lou ◽  
Ali Mohtat ◽  
...  
Keyword(s):  
Large Scale ◽  
Fluid Structure Interaction ◽  
Basin Modeling ◽  
Wave Impact ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Wave Basin ◽  
Impact Phenomena

The Ocean Cleanup System 001 Performance During Towing and Seakeeping Tests

2019 ◽  
Author(s):  
Joost Sterenborg ◽  
Nicola Grasso ◽  
Rogier Schouten ◽  
Arjen Tjallema
Keyword(s):  
Fluid Structure Interaction ◽  
Model Tests ◽  
Operating Conditions ◽  
Image Correlation ◽  
Plastic Pollution ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Wave Basin ◽  
Floating System ◽  
Floating Systems

Abstract One of the aims of The Ocean Cleanup is to develop technologies to extract plastic pollution from the world’s oceans. Several concepts of passive floating systems were considered that are supposed to confine plastics to ease their collection. Such concepts consist of a floating member and a submerged flexible skirt and have in common that their span is generally more than 500 meters. Consequently, fluid-structure interaction plays an important role in the response of such a floating system. To support numerical simulations, MARIN carried out extensive model tests on a 120 meter system section of the final concept, with focus on the fluid-structure interaction (FSI) of the submerged skirt in operating conditions and in towing configuration. The ability to capture plastics was not investigated in these model tests. Novel for wave-basin tests were non-intrusive measurements using underwater Digital Image Correlation (DIC) to obtain the displacements and deformations of the flexible skirt. DIC proved to be a capable measurement technique for this type of structure in combination with a wave basin. Detailed quantitative data on skirt motions and deformations were delivered and the last concept of the cleanup system was tested in the towing configuration and operational configuration.

Nonlinear Behaviors of Three Dimensional Sloshing in the LNG Elastic Tank

2021 ◽  
Author(s):  
Zhongchang Wang ◽  
Meirong Jiang ◽  
Yang Yu
Keyword(s):  
Natural Frequency ◽  
High Frequency ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Surface Elevation ◽  
Fluid Structure ◽  
Elastic Case ◽  
Structure Interaction ◽  
Elastic Tank ◽  
Sloshing Pressure

Abstract Aiming at the nonlinear sloshing in the LNG tank, a three-dimensional elastic model is established to investigate the fluid structure interaction effect. For the transient flow and the tank motion, the direct coupling method is employed to calculate the interaction between the sloshing and the bulkhead. The finite element software ADINA is adopted to do the computation. The sloshing natural frequency is verified with the results of the theoretical formula. Different wall thicknesses, filling ratios and external excitations are considered and the structure natural frequency, surface elevation and sloshing pressure are obtained. The results of the elastic case are further compared with the rigid results and the nonlinear characteristics are extracted to see the hydro-elastic effect. The sloshing natural frequencies are agreed well with the theoretical results. Due to the influence of the fluid structure interaction, the couple frequencies are obviously less than those of the empty tank. With the increase of the wall thickness, the frequencies of the empty tank and the couple frequencies all increase gradually. For the surface elevation, the thinner the bulkhead thickness is, the more the high frequency component is. The free surface is relatively flat and stable in the rigid tank but tend to be chaotic for the elastic one. Due to the fluid structure interaction, the sloshing pressure of the elastic case presents obvious high-frequency fluctuation and the sloshing pressure in the elastic tank is smaller than that in the rigid tank. This model clearly shows the valuable ability to solve the three dimensional sloshing in the elastic tank.

A Numerical Investigation of a Wave Energy Harness Device-Water Interaction System Subject to the Wave Maker Excitation in a Towing Tank

2009 ◽  
Author(s):  
Jing Tang Xing ◽  
Ye Ping Xiong ◽  
Ming Yi Tan ◽  
Huai Yu An
Keyword(s):  
Wave Energy ◽  
Water Surface ◽  
Fluid Structure Interaction ◽  
Energy Device ◽  
Fluid Structure ◽  
Towing Tank ◽  
Structure Interaction ◽  
Water Interaction ◽  
Interaction System ◽  
Wave Maker

This paper investigates numerically a wave energy harness device-water interaction system excited by a wave maker motion in order to extract maximum wave energy. The model of the energy harness device consists of a moving coil connected to a magnetic body floating on the water surface of the towing tank. At one end of the towing tank, a wave maker produces waves to excite the device-water interaction system. The motion of the coil relative to the magnetic body produces an electromagnetic induction voltage added to an energy collection circuit, so that the kinetic energy of the coil motion is transformed to electric energy. To extract maximum energy from the wave requires a large relative motion between the coil and the magnetic body of the energy harness device. To this end, the natural frequency of the wave energy harness device should be so close to the wave frequency that a resonance of the wave energy device can be reached. Since the wave energy device floats on the water surface, its dynamic behaviour is affected by the water motion. Therefore, it is necessary to consider fluid-structure interactions to design an effective wave energy device. This problem is addressed in this paper. In this numerical simulation, the water is considered as a compressible fluid satisfying a wave equation in the water domain in association with the boundary conditions on the free surface, wall and bottom of the towing tank. The wave maker motion is simulated by a given boundary acceleration on the wet interface of the wave maker. The energy harness device is treated as a two masses connected by four springs between them. The spring stiffness can be adjusted to obtain an effective energy extraction device. On the interface between the magnetic body and the water, the equilibrium and motion consistent conditions are required. The governing equations describing the fluid-structure interaction dynamics of the integrated system are presented. A corresponding variational principle is formulated and a mixed finite element model is established. The developed computer program-FSIAP is used to complete the numerical simulations. Suitable parameters of the energy harness device are obtained. The dynamic responses of the integrated fluid-structure interaction system excited by the wave maker motions are calculated. It is shown that the designed energy harness device can extract maximum wave energy using the resonance principle. The results obtained are compared and discussed. Some guidelines for engineering applications are provided.

Curved slender structures in non-uniform flows

1999 ◽  
Vol 385 ◽  
pp. 21-40 ◽  
Author(s):  
A. R. GALPER ◽  
T. MILOH
Keyword(s):  
Flow Field ◽  
Cross Section ◽  
Potential Flow ◽  
Load Distribution ◽  
Fluid Structure Interaction ◽  
General Analysis ◽  
Small Cross Section ◽  
Fluid Structure ◽  
Cylindrical Structure ◽  
Structure Interaction

General expressions are derived for the load distribution acting on an arbitrary curved and twisted rigid or deformable slender cylindrical structure moving in an ambient non-uniform potential flow field. Further simplifications are presented for flexible shapes in the limit of a small cross-section. The general analysis is illustrated for straight, toroidal and helical shapes. These shapes are frequently encountered in nature and are good examples of typical fluid–structure interaction problems.

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.

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