Impact of trim on added resistance of KRISO container ship (KCS) in head waves: An experimental and numerical study

Added resistance in waves is one of the main causes of an increase in required power when a ship operates in actual service conditions. The assessment of added resistance in waves is important from both an economic and environmental point of view, owing to increasingly stringent rules set by the International Maritime Organization (IMO) with the aim to reduce CO2 emission by ships. For that reason, it is desirable to evaluate the added resistance in waves already in the preliminary ship design stage both in regular and irregular waves. Ships are traditionally designed and optimized with respect to calm water conditions. Within this research, the effect of prismatic coefficient, longitudinal position of the centre of buoyancy, trim, pitch radius of gyration, and ship speed on added resistance is investigated for the KCS (Kriso Container Ship) container ship in regular head waves and for different sea states. The calculations are performed using the 3D panel method based on Kelvin type Green function. The results for short waves are corrected to adequately take into account the diffraction component. The obtained results provide an insight into the effect of variation of ship characteristics on added resistance in waves.

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Added Powering Measurements of KCS Maneuvering in Regular Variable Heading Waves

10.5957/attc-2017-0004 ◽

2017 ◽

Author(s):

Yugo Sanada ◽

Shogo Ito ◽

Yasuyuki Toda ◽

Frederick Stern

Keyword(s):

Scale Effects ◽

Open Water ◽

Container Ship ◽

Added Resistance ◽

Oblique Waves ◽

Wave Basin ◽

Head Waves ◽

Regular Variable ◽

Free Running ◽

Thrust And Torque

To know more detail of added powering and propeller load fluctuations in regular waves during free-maneuvering, free-running tests of KRISO Container Ship model (KCS) are conducted. KCS 2.7 m model that was used in the previous surge-free added resistance experiments is modified and new free-running system with compact dynamometer is installed. Free-running tests in calm water and in regular variable heading waves are performed at IIHR 40 m × 20 m × 3 m wave basin to obtain 6DOF motions with thrust/torque data. Propeller open water tests were performed at Osaka University towing tank (OU). To evaluate facility bias and scale effects, trajectories, motions and maneuvering characteristic parameters are compared with those of different size model taken at other facilities. Free-running course keeping tests in regular variable heading waves are performed as same conditions with Tokyo 2015 A Workshop on CFD in Ship Hydrodynamics (T2015) case 2.10 and case 2.11. Those results are compared with the data taken at FORCE with 6 m free-running model and OU with 3.2 m model by surge-free mount. In head waves, trends of RAO for heave and pitch are the same under surge-free and free-running. Added thrust/torque and propeller open water efficiency reduction of IIHR and OU become maximum at λ/ L=1.15 where the added resistance was maximum under surge-free condition. In oblique waves, added thrust and torque become larger where the wave encounter angle is from 0° to 45° and both trends agree with other type of container ship. Thrust and torque fluctuations of KCS become larger in beam and following waves. Variation of self-propulsion factors due to wave encounter angles are small in oblique waves.

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NUMERICAL SIMULATIONS OF ADDED RESISTANCE IN REGULAR HEAD WAVES ON A CONTAINER SHIP

Brodogradnja ◽

10.21278/brod70204 ◽

2019 ◽

Vol 70 (2) ◽

pp. 61-86 ◽

Cited By ~ 1

Author(s):

Young-Gill Lee ◽

◽

Cheolho Kim ◽

Jeong-Ho Park ◽

Hyeongjun Kim ◽

...

Keyword(s):

Numerical Simulations ◽

Container Ship ◽

Added Resistance ◽

Head Waves ◽

Regular Head Waves

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Added Resistance and 2DOF Motion Analysis of KVLCC2 in Regular Head Waves using Dynamic Overset Scheme

Journal of the Society of Naval Architects of Korea ◽

10.3744/snak.2018.55.5.385 ◽

2018 ◽

Vol 55 (5) ◽

pp. 385-393 ◽

Cited By ~ 1

Author(s):

Yoo-Chul Kim ◽

Yoonsik Kim ◽

Jin Kim ◽

Kwang-Soo Kim

Keyword(s):

Motion Analysis ◽

Added Resistance ◽

Head Waves ◽

Regular Head Waves

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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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Numerical Study of Two Vessels Seakeeping in Waves

Volume 8A: Ocean Engineering ◽

10.1115/omae2014-23269 ◽

2014 ◽

Author(s):

Dexin Zhan ◽

Don Bass ◽

David Molyneux

Keyword(s):

Objective Function ◽

Degrees Of Freedom ◽

Numerical Study ◽

Wave Direction ◽

Small Motion ◽

Head Waves ◽

Close Proximity ◽

Connection Line ◽

Sheltering Effect ◽

The Waves

This paper presents a numerical study of seakeeping in regular waves for two vessels in close proximity using commercial seakeeping software HydroStar and an in-house code MOTSIM. The objective was to study the possible sheltering effect of the larger vessel (FPSO) on the smaller one (OSV) during personnel transfer between the two vessels, where one vessel was at some angle relative to the other vessel and there was no connection line between them. The study mainly focused on the OSV motion resulting from the interaction of the FPSO when the OSV was at different headings and wave directions. Initially the OSV motions close to the FPSO (and parallel) were compared with those for the OSV alone. For an un-parallel position of the two vessels, an objective function based on the OSV RAOs motion in roll, pitch and heave directions was used to optimize the OSV position. Finally comparisons between HydroStar and MOTSIM results are provided. The main conclusions are: 1) When the FPSO and OSV are located in parallel, the OSV motions in sway, roll and yaw are larger than the single OSV motions in head waves while surge, heave and pitch are almost the same. The OSV motions in most of the six degrees of freedom are smaller than the single OSV motions when the waves are from other directions (always on the port side of the FPSO), which means that there is a sheltering effect. 2) The simulation results from different OSV rotation angles show that the hydrodynamic interaction between the FPSO and OSV e.g. the sheltering effect is related to the OSV angle and the wave heading. The objective function in roll, pitch and heave RAOs indicates that the OSV should maintain a close to parallel position with the FPSO to minimize motion when the waves come from the port side of the FPSO from 180 to 240 degrees. When the wave direction is around 240 degrees the OSV should have relatively small motion in waves for any OSV rotation angle. 3) A comparison of HydroStar and MOTSIM results shows that the MOTSIM results of a single vessel seakeeping simulation is in a good agreement with HydroStar. In two vessels situation more validation work needs to be done.

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Experiments and Computations for KCS Added Resistance for Variable Heading

10.5957/wmtc-2015-149 ◽

2015 ◽

Author(s):

Hamid Sadat-Hosseini ◽

Serge Toxopeus ◽

Dong Hwan Kim ◽

Teresa Castiglione ◽

Yugo Sanada ◽

...

Keyword(s):

Surface Profile ◽

Engine Performance ◽

Head Wave ◽

Added Resistance ◽

Local Flow ◽

Wake Field ◽

Head Waves ◽

Calm Water ◽

Free Surface Profile ◽

Peak Location

Experiments, CFD and PF studies are performed for the KCS containership advancing at Froude number 0.26 in calm water and regular waves. The validation studies are conducted for variable wavelength and wave headings with wave slope of H/λ=1/60. CFD computations are conducted using two solvers CFDShip-Iowa and STAR-CCM+. PF studies are conducted using FATIMA. For CFD computations, calm water and head wave simulations are performed by towing the ship fixed in surge, sway, roll and yaw, but free to heave and pitch. For variable wave heading simulations, the roll motion is also free. For PF, the ship model moves at a given speed and the oscillations around 6DOF motions are computed for variable wave heading while the surge motion for head waves is restrained by adding a very large surge damping. For calm water, computations showed E<4%D for the resistance,<8%D for the sinkage, and <40%D for the trim. In head waves with variable wavelength, the errors for first harmonic variables for CFD and PF computations were small, <5%DR for amplitudes and <4%2π for phases. The errors for zeroth harmonics of motions and added resistance were large. For the added resistance, the largest error was for the peak location at λ/L=1.15 where the data also show large scatter. For variable wave heading at λ/L=1.0, the errors for first harmonic amplitudes were <17%DR for CFD and <26%DR for PF. The comparison errors for first harmonic phases were E<24%2π. The errors for the zeroth harmonic of motions and added resistance were again large. PF studies for variable wave headings were also conducted for more wavelength condition, showing good predictions for the heave and pitch motions for all cases while the surge and roll motions and added resistance were often not well predicted. Local flow studies were conducted for λ/L=1.37 to investigate the free surface profile and wake field predicted by CFD. The results showed a significant fluctuation in the wake field which can affect the propeller/engine performance. Additionally it was found that the average propeller inflow to the propeller is significantly higher in waves.

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Head Wave Simulation of a KCS Model Using OpenFOAM for the Assessment of Sea-Margin

10.1115/omae2021-63827 ◽

2021 ◽

Author(s):

Hafizul Islam ◽

C. Guedes Soares

Keyword(s):

Head Wave ◽

Container Ship ◽

Added Resistance ◽

Free Condition ◽

Wave Simulation ◽

Calm Water ◽

Sinkage And Trim ◽

Simulation Results ◽

Design Speed ◽

Propulsion Power

Abstract The paper presents calm water and head wave simulation results for a KRISO Container Ship (KCS) model. All simulations have been performed using the open source CFD toolkit, OpenFOAM. Initially, a systematic verification study has been performed using the ITTC guideline to assess the simulation associated uncertainties. After that, a validation study has been performed to assess the accuracy of the results. Next, calm water simulations have been performed with sinkage and trim free condition at varying speeds. Later, head wave simulations have been performed with heave and pitch free motion. Simulations were repeated for varying wave lengths to assess the encountered added resistance by the ship in design speed. The results have been validated against available experimental data. Finally, power predictions have been made for both calm water and head wave cases to assess the required propulsion power. The paper tries to assess the validity of using 25% addition as sea margin over calm water prediction to consider wave encounters.

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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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