Numerical Investigation of the Motion Characteristics of Cylindrical Floating Body in Waves Using the Volume of Fluid Method

2021 ◽  
Vol 163 (A3) ◽  
Author(s):  
X Song ◽  
W Liu ◽  
T Xia
Keyword(s):  
Volume Of Fluid ◽  
Full Scale ◽  
Hydrodynamic Performance ◽  
Floating Body ◽  
Computational Domain ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Numerical Wave ◽  
Wave Conditions ◽  
Motion Characteristics

In this paper, a numerical hydrodynamic performance assessment of a full scale cylindrical floating body with different damping devices is presented. The motion characteristics of the full scale cylindrical floating body are investigated in regular and irregular wave conditions with different wave heights and periods. A numerical wave tank based on the two-phase Volume of Fluid (VOF) model was established. Approaches to the computational domain and overset-grids were investigated and were found to be suitable. Grid convergence was undertaken for the simulations. The numerical wave tank was performed to analyse the motion characteristics of the cylindrical floating body with arbitrary devices under different wave conditions by using the VOF method with an overset-grid technique. The motion characteristics of the cylindrical floating body with different damping devices were numerically investigated to provide more information on the effect of damping devices on the hydrodynamic performance. The conclusions of this paper give guidance in the motion characteristics and the damping device prototype design to be adopted under the specified wave conditions. 

scholarly journals Hydrodynamic Analysis of Ship with Well Deck in the Linear Numerical Wave Tank

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Gang Xu ◽  
Tian-Rui Mei ◽  
Ming-Liang Hu ◽  
Zhen Chen ◽  
Jun-Ming Hu
Keyword(s):  
Hydrodynamic Performance ◽  
Research Progress ◽  
Floating Body ◽  
Hydrodynamic Effect ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Hydrodynamic Analysis ◽  
Numerical Wave ◽  
The Government ◽  
Set Up

In recent years, the development and construction of islands and reefs has been proposed by the government and commercial company. However, as a large cargo carrier cannot reach islands and reefs if the harbor is not available, such type of carrier which has well deck is designed to meet the requirements of delivering people and equipment. It is a possible way to connect the island and supply cargo ships. This paper firstly summarizes the domestic and foreign research progress of hydrodynamic analysis of ships with well deck. Then, based on the CFD (Computational Fluid Dynamics) tools, we set up a linear numerical wave tank and study the hydrodynamic performance of original Wigley-III ship and modified Wigley-III ship with well deck. The hydrodynamic effect of the floating body in the well deck has been investigated and discussed.

Nonlinear Time-Domain Simulation of the Heaving-Buoy Type Wave Energy Converter by Using Three-Dimensional Potential Numerical Wave Tank Under Irregular Wave Conditions

2020 ◽  
Author(s):  
Sung-Jae Kim ◽  
Weoncheol Koo ◽  
Moo-Hyun Kim
Keyword(s):  
Wave Energy ◽  
Time Domain ◽  
Three Dimensional ◽  
Wave Energy Converter ◽  
Hydrodynamic Performance ◽  
Numerical Wave Tank ◽  
Energy Converter ◽  
Wave Tank ◽  
Type Wave ◽  
Numerical Wave

Abstract The aim of this paper is to evaluate the hydrodynamic performance of a heaving buoy type wave energy converter (WEC) and power take-off (PTO) system. To simulate the nonlinear behavior of the WEC with PTO system, a three-dimensional potential numerical wave tank (PNWT) was developed. The PNWT is a numerical analysis tool that can accurately reproduce experiments in physical wave tanks. The developed time-domain PNWT utilized the previously developed NWT technique and newly adopted the side wall damping area. The PNWT is based on boundary element method with constant panels. The mixed Eulerian-Lagrangian method (MEL) and acceleration potential approach were adopted to simulate the nonlinear behaviors of free-surface nodes associated with body motions. The PM spectrum as an irregular incident wave condition was applied to the input boundary. A floating or fixed type WEC structure was placed in the center of the computational domain. A hydraulic PTO system composed of a hydraulic cylinder, hydraulic motor and generator was modeled with approximate Coulomb damping force and applied to the WEC system. Using the integrated numerical model of the WEC with PTO system, nonlinear interaction of irregular waves, the WEC structure, and the PTO system were simulated in the time domain. The optimal hydraulic pressure of the PTO condition was predicted. The hydrodynamic performance of the WEC was evaluated by comparing the linear and nonlinear analytical results and highlighted the importance accounting for nonlinear free surfaces.

scholarly journals Estimation of Wave Loads Acting on Stationary Floating Body Using Viscous Numerical Wave Tank Technique

2013 ◽  
Vol 27 (3) ◽  
pp. 43-52
Author(s):  
Kyung-Mi Kim ◽  
Jae-Kyung Heo ◽  
Se-Min Jeong ◽  
Jong-Chun Park ◽  
Wu-Joan Kim ◽  
...  
Keyword(s):  
Floating Body ◽  
Wave Loads ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Numerical Wave

Numerical Wave Tank Analysis of Wave Run-Up on a Truncated Vertical Cylinder

2011 ◽  
Author(s):  
Jang Kim ◽  
Rajeev Jaiman ◽  
Steve Cosgrove ◽  
Jim O’Sullivan
Keyword(s):  
Wave Solution ◽  
Field Potential ◽  
The Body ◽  
Far Field ◽  
Computational Domain ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Closure Condition ◽  
Potential Wave ◽  
Numerical Wave

A new far-field closure condition for a CFD-based numerical wave tank that uses a potential wave solution to overlay the outer computational domain of a CFD solution is described. A prescribed potential wave solution covers the region beyond a diameter more than 10 times of floater footprints. The diffracted waves from the body are absorbed by the ‘potential-attractor’ terms applied in the intermediate CFD domain where the CFD solution for Navier-Stokes equation is gradually blended into far-field potential solution. The proposed model provides an efficient numerical wave tank for the case when incoming wave length is much longer than floater. In this case, the required mesh and domain size for numerical accuracy is mainly affected by the floater geometry and local wave kinematics near the floater and less dependent on the length scale of the incoming waves. The new numerical wave tank is first tested for a diffraction of a truncated cylinder exposed to long regular waves. Comparison with theoretical and experimental results demonstrates accuracy and efficiency of the new method.

A 2D Nonlinear Numerical Wave Tank With a Moored Floating Body

2019 ◽  
Author(s):  
Hui Sun ◽  
Jens B. Helmers
Keyword(s):  
Floating Body ◽  
Wave Steepness ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Strongly Nonlinear ◽  
Motion Responses ◽  
Numerical Wave ◽  
Numerical Solver ◽  
The Time Domain ◽  
Horizontal Circular Cylinder

Abstract A 2D nonlinear numerical wave tank is developed to simulate the motion responses of a moored floating body in waves which may experience strongly nonlinear wave-body interactions. The numerical solver is based on a Boundary Element Method which has been developed to solve strongly nonlinear hydrodynamic problems. The method is further developed in this paper to simulate a floating body in waves, where horizontal, vertical and rotational motions can be calculated. An effective algorithm is implemented to separate the added mass forces from the total hydrodynamic forces, thus to make the time domain solution converge more easily. The numerical results for a horizontal circular cylinder in waves are compared with linear theory for small wave steepness for verification and further compared with published model tests and CFD results for high wave steepness as validations.

Understanding Regular Waves Effect on Ship by Numerical Wave Tank Simulation

2013 ◽  
Vol 477-478 ◽  
pp. 259-264
Author(s):  
Shaotao Fan ◽  
Cheng Bi Zhao ◽  
You Hong Tang
Keyword(s):  
Three Dimensional ◽  
Unsteady Motion ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Continuity Equations ◽  
Numerical Wave ◽  
Volume Method ◽  
Marine Floating Structures

This study establishes three-dimensional numerical wave tank based on the theory of viscous flow to simulate the unsteady motion response of a Wigley advancing in regular heading waves. The governing equations, Reynolds Averaged Navier-Stokes and continuity equations are discretized by finite volume method, a Reynolds-averaged NavierStokes solver is employed to predict the motions of ship, and volume of fluid method is adopted to capture the nonlinear free surface by writing user-defined functions. The outgoing waves are dissipated inside an artificial damping zone located at the rear part (about 1-2 wave lengths) of the wave tank. The numerical simulation results are compared with theoretical and experimental data from Delft University of Technology, and show good agreement with them. This research can be used to further analyze and predict hydrodynamic performance of ship and marine floating structures in waves and help to extend the applications of numerical wave tank.

Sign in / Sign up

Export Citation Format

Share Document