Time domain simulation of side-by-side floating bodies using a 3D numerical wave tank approach

Abstract The coupled system of two side-by-side fixed and/or floating bodies interacting with a large amplitude nonlinear wave is studied using a direct time domain solution method. The numerical model is based on a three-dimensional mixed Eulerian–Lagrangian (MEL) method under certain simplifying approximations permitting Rankine panel scheme to be implemented over a time-invariant boundary surface to solve the boundary value problem for the unknown velocity potentials. A 4th order Adams–Bashforth–Moulton scheme is used for time marching of rigid-body motion histories of the individual bodies and evolution of the free-surface including the gap region in which large resonant fluid motions occur. A systematic study has been carried out to evaluate the performance of the developed time domain method in simulating the forces and motions as well as the fluid motion in the gap region for the two body system under various arrangements and in different wave-headings. At first, the computed numerical results have been validated and verified with computational and experimental results available in literature for standard geometries such as vertical truncated cylinders and rectangular boxes. Secondly, effectiveness of the damping lid model which is introduced to suppress wave resonance in the gap region is investigated including its influence on maximum sway forces on fixed and floating rectangular barges in side-by-side configurations. Thirdly, comparative studies on absolute and relative motion response for two cases (two rectangular barges, and a FLNG-FPSO + shuttle tanker) in side-by-side arrangement are detailed to bring out the importance of nonlinearities arising due to steep nonlinear incident waves. Finally, coupled motions of the two-body system of an FPSO and a shuttle tanker floating in side-by-side configuration in a steep nonlinear wave field are studied in which the two bodies are connected through hawsers, and also the FPSO is moored to the ground. Additionally there is a fender between the two bodies.

[1]  David Le Touzé,et al.  Non‐linear time‐domain models for irregular wave diffraction about offshore structures , 2003 .

[2]  Ren-chuan Zhu,et al.  A Time Domain Investigation on the Hydrodynamic Resonance Phenomena of 3-D Multiple Floating Structures , 2008 .

[3]  Fournier Jean-Robert,et al.  Hydrodynamics of Two Side-by-side Vessels Experiments And Numerical Simulations , 2006 .

[4]  Jaap de Wilde,et al.  Numerical Multiple-Body Simulations of Side-by-Side Mooring to an FPSO , 2001 .

[5]  R Cointe,et al.  NONLINEAR AND LINEAR MOTIONS OF A RECTANGULAR BARGE IN A PERFECT FLUID , 1991 .

[6]  C. Soares,et al.  Safe offloading from floating LNG platforms , 2015 .

[7]  Koichiro Yoshida,et al.  Hydrodynamic interaction between multiple three-dimensional bodies of arbitrary shape in waves , 1989 .

[8]  John D. Fenton,et al.  A Fourier approximation method for steady water waves , 1981, Journal of Fluid Mechanics.

[9]  Ming-Chung Fang,et al.  The relative motion and wave elevation between two floating structures in waves , 2001 .

[10]  Qingwei Ma,et al.  Numerical Investigations On Responses of Two Moored 3D Floating Structures to Steep Waves , 2008 .

[11]  Robert F. Beck,et al.  The acceleration potential in fluid–body interaction problems , 2011 .

[12]  Liang Sun,et al.  Wave driven free surface motion in the gap between a tanker and an FLNG barge , 2015 .

[13]  R. Huijsmans,et al.  Advances in the Hydrodynamics of Side-by-Side Moored Vessels , 2007 .

[14]  B. Teng,et al.  Modelling of multi-bodies in close proximity under water waves—Fluid forces on floating bodies , 2011 .

[15]  Wenhua Zhao,et al.  Prediction of hydrodynamic performance of an FLNG system in side-by-side offloading operation , 2014 .

[16]  R. E. Taylor,et al.  Diffraction and independent radiation by an array of floating cylinders , 2008 .

[17]  Debabrata Sen,et al.  Time-domain simulation of large-amplitude wave–structure interactions by a 3D numerical tank approach , 2015 .

[18]  Jianmin Yang,et al.  Hydrodynamics of an FLNG system in tandem offloading operation , 2013 .

[19]  Masashi Kashiwagi,et al.  Wave drift forces and moments on two ships arranged side by side in waves , 2005 .

[20]  Sa Young Hong,et al.  Numerical and experimental study on hydrodynamic interaction of side-by-side moored multiple vessels , 2003 .

[21]  Tim Bunnik,et al.  Hydrodynamic Analysis For Side-by-Side Offloading , 2009 .

[22]  Katsuji Tanizawa.  Long Time Fully Nonlinear Simulation of Floating Body Motions with Artificial Damping Zone , 1996 .

[23]  Sa Young Hong,et al.  Numerical analysis of various artificial damping schemes in a three-dimensional numerical wave tank , 2014 .

[24]  T ShivajiGanesan,et al.  Direct time domain analysis of floating structures with linear and nonlinear mooring stiffness in a 3D numerical wave tank , 2015 .

[25]  Liang Cheng,et al.  Numerical simulation and comparison of potential flow and viscous fluid models in near trapping of narrow gaps , 2010 .

[26]  Rafael A. Watai,et al.  Rankine time-domain method with application to side-by-side gap flow modeling , 2015 .

[27]  X. Feng,et al.  Wave resonances in a narrow gap between two barges using fully nonlinear numerical simulation , 2015 .

[28]  Kyong-Hwan Kim,et al.  Time-Domain Analysis of Motion Responses of Adjacent Multiple Floating Bodies in Waves , 2008 .

[29]  R. H. M. Huijsmans,et al.  Diffraction and Radiation of Waves Around Side-by-Side Moored Vessels , 2001 .

[30]  Moo-Hyun Kim,et al.  Hydrodynamic interactions and relative motions of two floating platforms with mooring lines in side-by-side offloading operation , 2005 .

[31]  Bernard Molin,et al.  Experimental and numerical study of the gap resonances in-between two rectangular barges. , 2009 .

[32]  C. Guedes Soares,et al.  Numerical study of the coupled motion responses in waves of side-by-side LNG floating systems , 2015 .

[33]  Edward M. Lewandowski,et al.  Multi-vessel seakeeping computations with linear potential theory , 2008 .

[34]  Mun-Sung Kim,et al.  Prediction of Motion Responses between Two Offshore Floating Structures in Waves , 2002 .

[35]  Yoshiyuki Inoue,et al.  A STUDY ON MOTIONS AND DRIFT FORCES OF A MULTIBODY FLOATING SYSTEM IN WAVES , 2000 .

[36]  Jens Kirkegaard,et al.  Multi Vessel Interaction in Shallow Water , 2009 .

[37]  Jaap de Wilde,et al.  Time Domain Simulations of Side-by-Side Moored Vessels: Lessons Learnt From a Benchmark Test , 2007 .

[38]  W. Cummins.  THE IMPULSE RESPONSE FUNCTION AND SHIP MOTIONS , 2010 .

[39]  W. E. Cummins,et al.  The Impulse Response Function and Ship Motion , 1962 .