Numerical Simulation on the Greenwater Impact Load of Offshore Structure in Regular Waves

2017 ◽  
Vol 54 (6) ◽  
pp. 492-500
Author(s):  
Ui-Ha Kang ◽  
Young-Gill Lee ◽  
In-Jun Yang ◽  
Ki-Yong Kim ◽  
Young-Seok Joo ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Impact Load ◽  
Regular Waves ◽  
Offshore Structure

Diffraction Waves About an Advancing Wedge Model in Deep Water

1990 ◽  
Vol 34 (02) ◽  
pp. 105-122
Author(s):  
Hideaki Miyata ◽  
Makoto Kanai ◽  
Noriaki Yoshiyasu ◽  
Yohichi Furuno
Keyword(s):  
Numerical Simulation ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Wedge Angle ◽  
Wave Pattern ◽  
Regular Waves ◽  
Nonlinear Characteristics ◽  
Diffracted Waves ◽  
Nonlinear Features ◽  
Incident Waves

The diffraction of regular waves by advancing wedge models is studied both experimentally and numerically. The nonlinear features of diffracted waves are visualized by wave pattern pictures and the formation is analyzed by the grid-projection method. The experimental observation indicates that the diffracted waves have a number of nonlinear characteristics similar to shock waves due to the interaction of incident waves with the advancing obstacle in the flow-field caused by the advancing motion. Bow waves of both oblique type and normal detached type are observed at remarkably lower Froude numbers than in the case of a ship in steady advance motion. Their occurrence systematically depends on the Froude number and the wedge angle. The numerical simulation of this phenomenon by a finite-difference method shows approximate agreement with the experimental results.

Numerical simulation of regular waves: Optimization of a numerical wave tank

2018 ◽  
Vol 170 ◽  
pp. 89-99 ◽  
Author(s):  
Fábio M. Marques Machado ◽  
António M. Gameiro Lopes ◽  
Almerindo D. Ferreira
Keyword(s):  
Numerical Simulation ◽  
Numerical Wave Tank ◽  
Regular Waves ◽  
Wave Tank ◽  
Numerical Wave

Force Analysis of the Anchor Chains and the Cable in the Crane-System with a Floating Base in Regular Waves

2014 ◽  
Vol 494-495 ◽  
pp. 321-327
Author(s):  
Ya Xin Huang ◽  
Bing Wang ◽  
Jun Yi Liu
Keyword(s):  
Numerical Simulation ◽  
Discrete Time ◽  
Time History ◽  
Roll Motion ◽  
Force Analysis ◽  
Time Transfer ◽  
Regular Waves ◽  
Body Model ◽  
Floating Base ◽  
Rigid Body Model

In order to analyze the force of the anchor chains and the cable in the crane-system with a floating base, firstly the system is simplified to two-rigid-body model and the anchor chains in the system are in symmetric layout; then the motion response of the system as well as the force of the anchor chains and the cable are solved by use of discrete time transfer matrix method, lastly the time history curves of motion of the system and the force of the anchor chains and the cable are obtained. The results of numerical simulation show that the roll motion has greater influences on the system comparing with sway and heave, the amplitudes of sway and heave are small. Furthermore, the force of the anchor chains are mainly caused by the roll motion while the force caused by sway and heave are relatively small.

Numerical Simulation and Experimental Study on Fluid-Filled Hemispherical Shell under Impact

2013 ◽  
Vol 364 ◽  
pp. 172-176
Author(s):  
Hui Wei Yang ◽  
Bin Qin ◽  
Zhi Jun Han ◽  
Guo Yun Lu
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Impact Load ◽  
Elastic Recovery ◽  
Plastic Hinge ◽  
Time History ◽  
Hemispherical Shell ◽  
History Of ◽  
Local Impact ◽  
The Impact

The dynamic response of fluid-filled hemispherical shell in mass impact is studied by experiment using DHR9401. Combining the time history of impact force with experimental observation of the deformation process, it can be seen that the dynamic response can be divided into four stages: the flattening around the impact point, the forming and expanding outward of shell plastic hinge, the plastic edge region flatten by the punch, and elastic recovery. The experimental results show that: Because the shell filled with liquid, the local impact load that the shell suffered is translated into area load and loads on the inner shell uniformly, so that it has a high carrying capacity. Numerical simulation is used to study the time history of energy absorption of different shell structures. The result shows that the crashworthiness of sandwich fluid-filled shell is improved greatly. Under the certain impact energy, deformation of its inner shell is very small, which can provide effective security space.

Numerical Simulation of Two-Phase Sloshing Flow in LNG Tank Using Finite-Analytic Level-Set Method

2007 ◽  
Author(s):  
Kai Yu ◽  
Hamn-Ching Chen ◽  
Jang Whan Kim ◽  
Young-Bum Lee
Keyword(s):  
Numerical Simulation ◽  
Wave Breaking ◽  
Impact Load ◽  
Three Dimensional ◽  
Impact Pressure ◽  
Staggered Grid ◽  
Two Phase ◽  
Local Flow ◽  
Hull Structure ◽  
Lng Tank

Impact pressure due to sloshing is of great concern for the ship owners, designers and builders of the LNG carriers regarding the safety of LNG containment system and hull structure. Sloshing of LNG in a partially filled tank has been an active area of research with numerous experimental and numerical investigations over the past decade. In order to accurately predict the sloshing impact load, it is necessary to develop advanced numerical simulation tools which can provide accurate resolution of local flow phenomena including wave breaking, jet formation, gas entrapping and liquid-gas interactions. In the present study, a new numerical method is developed for the simulation of violent sloshing flow inside a three-dimensional LNG tank considering wave breaking and liquid-gas interaction. The sloshing flow inside a membrane-type LNG tank is simulated numerically using the Finite-Analytic Navier-Stokes (FANS) method. The governing equations for two-phase air and water flows are formulated in curvilinear coordinate system and discretized using the finite-analytic method on a non-staggered grid. Simulations were performed for LNG tank in transverse and longitudinal motions including horizontal, vertical, and rotational motions. The predicted impact pressures were compared with the corresponding experimental data. The validation results clearly illustrate the capability of the present two-phase FANS method for accurate prediction of impact pressure in sloshing LNG tank including violent free surface motion, three-dimensional instability and air trapping effects.

419 Dynamic Behavior and Numerical Simulation of Curtain-Cables Subjected to Impact Load

2004 ◽  
Vol 2004 (0) ◽  
pp. _419-1_-_419-3_
Author(s):  
Masato OGAWA ◽  
Masahiro WATANABE ◽  
Nobuyuki KOBAYASHI
Keyword(s):  
Numerical Simulation ◽  
Dynamic Behavior ◽  
Impact Load

Experimental Investigation of Ice Mass Hydrodynamic Interaction With Offshore Structure in Close Proximity

2015 ◽  
Author(s):  
Tanvir Mehedi Sayeed ◽  
Bruce Colbourne ◽  
Heather Peng ◽  
Benjamin Colbourne ◽  
Don Spencer
Keyword(s):  
Hydrodynamic Interaction ◽  
Impact Load ◽  
Numerical Study ◽  
Numerical Models ◽  
Offshore Structures ◽  
Ocean Engineering ◽  
Offshore Structure ◽  
Area Of Interest ◽  
Close Proximity ◽  
The Impact

Iceberg/bergy bit impact load with fixed and floating offshore structures and supply ships is an important design consideration in ice-prone regions. Studies tend to divide the iceberg impact problem into phases from far field to contact. This results in a tendency to over simplify the final crucial stage where the structure is impacted. The authors have identified knowledge gaps and their influence on the analysis and prediction of iceberg impact velocities and loads (Sayeed et. al (2014)). The experimental and numerical study of viscous dominated very near field region is the main area of interest. This paper reports preliminary results of physical model tests conducted at Ocean Engineering Research Center (OERC) to investigate hydrodynamic interaction between ice masses and fixed offshore structure in close proximity. The objective was to perform a systematic study from simple to complex phenomena which will be a support base for the development of subsequent numerical models. The results demonstrated that hydrodynamic proximity and wave reflection effects do significantly influence the impact velocities at which ice masses approach to large structures. The effect is more pronounced for smaller ice masses.

PID Control for Magnetorheological Elastomer Absorber with Impact Load

2011 ◽  
Vol 121-126 ◽  
pp. 1734-1738 ◽  
Author(s):  
Jie Fu ◽  
Miao Yu ◽  
Zhi Wei Xing
Keyword(s):  
Numerical Simulation ◽  
Mechanical Property ◽  
Mathematical Model ◽  
Control Strategy ◽  
Pid Control ◽  
Pid Controller ◽  
Impact Load ◽  
Variable Stiffness ◽  
Impact Testing ◽  
Magnetorheological Elastomer

In this paper, a semi-active impact control system, which consists of a new Magnetorehological elastomer (MRE) absorber with variable stiffness, is proposed and its vibration control with impact load is investigated. An impact testing platform is established and mechanical property of fabricated MRE is tested. Based on Newton’s law the appropriate mathematical model of MRE absorber system is established. PID controller for MRE absorber system is designed to reduce the effect of impact load. Finally, the effectiveness of control strategy is verified by numerical simulation.

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