Fully Coupled Analysis of Ship Motion and Sloshing Tanks in Regular and Irregular Waves

2018 ◽  
Author(s):  
Yuan Zhuang ◽  
Decheng Wan
Keyword(s):  
Open Source ◽  
Ship Motion ◽  
Irregular Waves ◽  
Coupled Analysis ◽  
Regular Waves ◽  
Wave Condition ◽  
Sloshing Phenomenon ◽  
Fully Coupled ◽  
Fully Coupled Analysis ◽  
External Wave

Fully coupled analysis of ship motion and sloshing tank in waves is essential for floating structures which store and transports natural gas. For partially filled tanks would generate violent sloshing due to external wave excitation, and the sloshing flow can consequently affect ship motion. Therefore, how to evaluate ship motion and sloshing phenomenon in tank is of great importance, especially under real sea state, when wave induced sloshing would be more complex than that under linear wave condition. In the present work, a CFD-based method is applied to simulate both external wave field and inner sloshing tank field in regular waves and irregular waves. The ship is a simplified FPSO, with two LNG tanks. All the numerical simulations are carried out by the in-house CFD code naoe-FOAM-SJTU, which is developed on the open source platform OpenFOAM. The regular and irregular wave condition is simulated based on open source toolbox waves2Foam. The main parameters of coupling effect of ship motion and sloshing tank, such as the time history of ship motion, sloshing phenomenon in tanks are obtained by our computations. The predicted results for the coupling effects of ship motion and sloshing tank in regular waves are compared with the corresponding experimental data. The comparison is satisfactory and shows that the CFD method has the ability to simulate coupling effects of ship motion and sloshing tank in waves.

A 3D fully coupled analysis of nonlinear sloshing and ship motion

2012 ◽  
Vol 39 ◽  
pp. 1-13 ◽  
Author(s):  
S. Mitra ◽  
C.Z. Wang ◽  
J.N. Reddy ◽  
B.C. Khoo
Keyword(s):  
Ship Motion ◽  
Coupled Analysis ◽  
Nonlinear Sloshing ◽  
Fully Coupled ◽  
Fully Coupled Analysis

Reliability Analysis of Short Term Mooring Tension of a Semi-Submersible System

2018 ◽  
Author(s):  
Sheng Xu ◽  
C. Guedes Soares ◽  
Ângelo P. Teixeira
Keyword(s):  
Reliability Analysis ◽  
Line Strength ◽  
Coupled Analysis ◽  
Mooring Line ◽  
Global Maximum ◽  
Hydrodynamic Drag ◽  
Sampling Point ◽  
Wave Condition ◽  
Drag Coefficients ◽  
Fully Coupled

A detail procedure to study mooring line strength reliability is presented. A fully coupled analysis is carried out to get the mooring tensions of a deep water semi-submersible floating systems operated in 100 year wave condition in South China Sea. The ACER method is applied to predict the 3h extreme mooring tension, and the results are validated by global maximum method. The hydrodynamic sampling points are generated by Latin Hypercube Sampling technique. The 3h extreme mooring tension is calculated by the ACER method with 10 minutes fully coupled dynamic simulation for each sampling point. The Kriging meta model method is trained to predict 3h mooring extreme tension under the effects of random hydrodynamic drag coefficients. A reliability analysis is carried out by implementing Monte Carlo simulation with the random hydrodynamic drag coefficients and mooring breaking strength considered.

Vortex Induced Vibration Analysis of a Complex Subsea Jumper

2010 ◽  
Author(s):  
Samuel Holmes ◽  
Yiannis Constantinides
Keyword(s):  
Complex Shape ◽  
Coupled Analysis ◽  
Eigenvalues And Eigenvectors ◽  
Element Analysis ◽  
Vortex Induced Vibration ◽  
Sea Floor ◽  
Curved Pipe ◽  
Design Analyses ◽  
Fully Coupled ◽  
Fully Coupled Analysis

Jumpers are typically short sections of curved pipe spanning production riser elements on the sea floor. When in areas of significant currents these jumpers are subject to vortex induced vibration (VIV). The complex shape of the jumper means that numerical methods are usually needed to solve for the vibration modes of the jumper. Furthermore, the fluid flow around the jumper is also complex so that traditional methods of VIV analysis used for risers are not applicable to jumpers. Here we use a CFD code in a fully coupled analysis to predict vibration response and strain of a typical subsea jumper. A separate finite element analysis is used to calculate the eigenvalues and eigenvectors of the jumper system for input into the CFD analysis. The resulting method is economical and practical for design analyses.

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