Numerical study of ship motions and added resistance in regular incident waves of KVLCC2 model

It is known that the added resistance in waves can be computed from ship-generated unsteady waves through the unsteady wave analysis method. To investigate the effects of nonlinear ship-generated unsteady waves and bluntness of the ship geometry on the added resistance, measurements of unsteady waves, wave-induced ship motions, and added resistance were carried out using two different (blunt and slender) modified Wigley models. The ship-generated unsteady waves are also produced by the linear superposition using the waves measured for the diffraction and radiation problems and the complex amplitudes of ship motions measured for the motion-free problem in waves. Then a comparison is made among the values of the added resistance by the direct measurement using a dynamometer and by the wave analysis method using the Fourier transform of measured and superposed waves. It is found that near the peak of the added resistance where ship motions become large, the degree of nonlinearity in the unsteady wave becomes prominent, especially at the forefront part of the wave. Thus, the added resistance evaluated with measured waves at larger amplitudes of incident wave becomes much smaller than the values by the direct measurement and by the wave analysis with superposed waves or measured waves at smaller amplitude of incident wave. Discussion is also made on the characteristics of the added resistance in the range of short incident waves.

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Numerical study of Iran-Bushehr Container Ship motions and added resistance in regular head waves using STAR-CCM+

مهندسی دریا ◽

10.29252/marineeng.16.31.41 ◽

2020 ◽

Vol 16 (31) ◽

pp. 41-52

Author(s):

Amirhossein Amiri ◽

Mohsen Shakeri ◽

Abas Ramiar ◽

Mostafa Jafarzadeh Khatibani ◽

◽

...

Keyword(s):

Numerical Study ◽

Ship Motions ◽

Container Ship ◽

Added Resistance ◽

Head Waves ◽

Regular Head Waves

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Numerical Study on Change of Added Resistance due to Incident Waves in Finite Water Depth

Journal of Waterway Port Coastal and Ocean Engineering ◽

10.1061/(asce)ww.1943-5460.0000526 ◽

2019 ◽

Vol 145 (6) ◽

pp. 04019025

Author(s):

Dong-Min Park ◽

Yonghwan Kim

Keyword(s):

Water Depth ◽

Numerical Study ◽

Added Resistance ◽

Finite Water Depth ◽

Incident Waves

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A numerical study: liquid sloshing dynamics in a tank due to uncoupled sway, heave and roll ship motions

Journal of Naval Architecture and Marine Engineering ◽

10.3329/jname.v10i2.16215 ◽

2013 ◽

Vol 10 (2) ◽

pp. 119-138 ◽

Cited By ~ 1

Author(s):

Nasar Thuvanismail ◽

Sannasiraj Sannasi ◽

Sundar Vallam

Keyword(s):

Numerical Study ◽

Energy Spectra ◽

Qualitative Assessment ◽

Ship Motions ◽

Theoretical Studies ◽

Sloshing Dynamics ◽

Tank System ◽

Liquid Depth ◽

Sloshing Phenomenon ◽

Heave Motion

In order to explore the physics implicated with the sloshing phenomenon subjected to independent regular sway, heave and roll excitations of the liquid tank system, theoretical studies are carried out. Four liquid fill levels with static liquid depth, hs, to the length, l of aspect ratio (hs/l) 0.163, 0.325, 0.488 and 0.585, are considered. The energy spectra of sloshing oscillation, their qualitative assessment and the harmonics present in the sloshing oscillation are studied. Frequency Response amplitude has also been presented. The study reveals that sway excites a particular mode of sloshing (primary harmonic) by fulfilling the resonance conditions and also excites secondary modes. However, the roll motion excites the first mode of sloshing irrespective of the excitation frequencies. The heave motion excites the particular mode which is assumed as an initial perturbation.DOI: http://dx.doi.org/10.3329/jname.v10i2.16215

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EFD and CFD Study of Forces, Ship Motions, and Flow Field for KRISO Container Ship Model in Waves

Journal of Ship Research ◽

10.5957/jsr.2020.64.1.61 ◽

2020 ◽

Vol 64 (01) ◽

pp. 61-80

Author(s):

Ping-Chen Wu ◽

Md. Alfaz Hossain ◽

Naoki Kawakami ◽

Kento Tamaki ◽

Htike Aung Kyaw ◽

...

Keyword(s):

Fluid Dynamics ◽

Flow Field ◽

Flow Simulation ◽

Wake Flow ◽

Ship Motions ◽

Container Ship ◽

Added Resistance ◽

Ocean Engineering ◽

Ship Model ◽

Calm Water

Ship motion responses and added resistance in waves have been predicted by a wide variety of computational tools. However, validation of the computational flow field still remains a challenge. In the previous study, the flow field around the Korea Research Institute for Ships and Ocean Engineering (KRISO) Very Large Crude-oil Carrier 2 tanker model with and without propeller condition and without rudder condition was measured by the authors, as well as the resistance and self-propulsion tests in waves. In this study, the KRISO container ship model appended with a rudder was used for the higher Froude number .26 and smaller block coefficient .65. The experiments were conducted in the Osaka University towing tank using a 3.2-m-long ship model for resistance and self-propulsion tests in waves. Viscous flow simulation was performed by using CFDShip-Iowa. The wave conditions proposed in Computational Fluid Dynamics (CFD) Workshop 2015 were considered, i.e., the wave-ship length ratio λ/L = .65, .85, 1.15, 1.37, 1.95, and calm water. The objective of this study was to validate CFD results by Experimental Fluid Dynamics (EFD) data for ship vertical motions, added resistance, and wake flow field. The detailed flow field for nominal wake and self-propulsion condition will be analyzed for λ/L = .65, 1.15, 1.37, and calm water. Furthermore, bilge vortex movement and boundary layer development on propeller plane, propeller thrust, and wake factor oscillation in waves will be studied.

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RANS investigation of influence of wave steepness on ship motions and added resistance in regular waves

Journal of Marine Science and Technology ◽

10.1007/s00773-018-0527-5 ◽

2018 ◽

Vol 23 (4) ◽

pp. 991-1003 ◽

Cited By ~ 2

Author(s):

Si Chen ◽

Takanori Hino ◽

Ning Ma ◽

Xiechong Gu

Keyword(s):

Ship Motions ◽

Wave Steepness ◽

Added Resistance ◽

Regular Waves

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Coupling of Sloshing and Ship Motions

Journal of Ship Research ◽

10.5957/jsr.2003.47.3.208 ◽

2003 ◽

Vol 47 (03) ◽

pp. 208-221 ◽

Cited By ~ 3

Author(s):

Olav F. Rognebakke ◽

Odd M. Faltinsen

Keyword(s):

Steady State ◽

Transient Behavior ◽

Frequency Domain Analysis ◽

Ship Motions ◽

Steady State Motion ◽

Constant Coefficients ◽

Incident Waves ◽

Violent Sloshing ◽

Different Levels ◽

Good Agreement

The coupled effect between ship motions and sloshing is studied. Two-dimensional experiments of a hull section containing tanks filled with different levels of water excited in sway by regular waves have been conducted. Steady-state results are obtained for the sway amplitude. Even if violent sloshing occurs in the tanks, the steady-state motion is almost linear and sinusoidal with the frequency of the linear incident waves. This implies that higher-order harmonics of the sloshing force are filtered out by the system. Simulations of the modeled case are performed using a linear and a nonlinear sloshing model and mainly assuming linear external flow. For steady-state motion, a convolution formulation does not improve the results relative to using constant coefficients in the equation of motion. However, in order to properly model the transient behavior in an irregular sea, a convolution formulation must be included. The treatment of the retardation function for the external problem is discussed in detail. A good agreement between experiments and computations is reported. The calculated coupled motion is sensitive to the damping of the sloshing motion in a certain frequency range where the coupled sloshing and ship motions cause resonant ship motions. A quasilinear frequency domain analysis is used to explain this by introducing the sloshing loads as a frequency dependent spring.

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NUMERICAL PREDICTION OF VERTICAL SHIP MOTIONS AND ADDED RESISTANCE

The International Journal of Maritime Engineering ◽

10.5750/ijme.v159ia4.1039 ◽

2021 ◽

Vol 159 (A4) ◽

Author(s):

F Cakici ◽

E Kahramanoglu ◽

A D Alkan

Keyword(s):

Deep Water ◽

High Speed ◽

Computer Experiments ◽

Navier Stokes ◽

Ship Motions ◽

Added Resistance ◽

Strip Theory ◽

Head Waves ◽

Computational Fluid Dynamics Cfd ◽

Volume Method

Along with the development of computer technology, the capability of Computational Fluid Dynamics (CFD) to conduct ‘virtual computer experiments’ has increased. CFD tools have become the most important tools for researchers to deal with several complex problems. In this study, the viscous approach called URANS (Unsteady Reynolds Averaged Navier-Stokes) which has a fully non-linear base has been used to solve the vertical ship motions and added resistance problems in head waves. In the solution strategy, the FVM (Finite Volume Method) is used that enables numerical discretization. The ship model DTMB 5512 has been chosen for a series of computational studies at Fn=0.41 representing a high speed case. Firstly, by using CFD tools the TF (Transfer Function) graphs for the coupled heave- pitch motions in deep water have been generated and then comparisons have been made with IIHR (Iowa Institute of Hydraulic Research) experimental results and ordinary strip theory outputs. In the latter step, TF graphs of added resistance for deep water have been generated by using CFD and comparisons have been made only with strip theory.

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Numerical Prediction of Vertical Ship Motions and Added Resistance

10.3940/rina.ijme.2017.a4.450 ◽

2017 ◽

Vol 159 (A4) ◽

Author(s):

F Cakici ◽

E Kahramanoglu ◽

A D Alkan

Keyword(s):

Deep Water ◽

High Speed ◽

Computer Experiments ◽

Navier Stokes ◽

Ship Motions ◽

Added Resistance ◽

Strip Theory ◽

Head Waves ◽

Computational Fluid Dynamics Cfd ◽

Volume Method

Along with the development of computer technology, the capability of Computational Fluid Dynamics (CFD) to conduct ‘virtual computer experiments’ has increased. CFD tools have become the most important tools for researchers to deal with several complex problems. In this study, the viscous approach called URANS (Unsteady Reynolds Averaged Navier-Stokes) which has a fully non-linear base has been used to solve the vertical ship motions and added resistance problems in head waves. In the solution strategy, the FVM (Finite Volume Method) is used that enables numerical discretization. The ship model DTMB 5512 has been chosen for a series of computational studies at Fn=0.41 representing a high speed case. Firstly, by using CFD tools the TF (Transfer Function) graphs for the coupled heave-pitch motions in deep water have been generated and then comparisons have been made with IIHR (Iowa Institute of Hydraulic Research) experimental results and ordinary strip theory outputs. In the latter step, TF graphs of added resistance for deep water have been generated by using CFD and comparisons have been made only with strip theory.

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