scholarly journals Full-Scale CFD Analysis of Double-M Craft Seakeeping Performance in Regular Head Waves

2021 ◽  
Vol 9 (5) ◽  
pp. 504
Author(s):  
Deniz Ozturk ◽  
Cihad Delen ◽  
Simone Mancini ◽  
Mehmet Ozan Serifoglu ◽  
Turgay Hizarci
Keyword(s):  
Full Scale ◽  
Stokes Wave ◽  
Added Resistance ◽  
Motion Responses ◽  
Seakeeping Performance ◽  
Head Waves ◽  
Calm Water ◽  
Maximum Improvement ◽  
Fifth Order ◽  
Regular Head Waves

This study presents the full-scale resistance and seakeeping performance of an awarded Double-M craft designed as a 15 m next-generation Emergency Response and Rescue Vessel (ERRV). For this purpose, the Double-M craft is designed by comprising the benchmark Delft 372 catamaran with an additional center and two side hulls. First, the resistance and seakeeping analyses of Delft 372 catamaran are simulated on the model scale to verify and compare the numerical setup for Fr = 0.7. Second, the seakeeping performance of the full-scale Double-M craft is examined at Fr = 0.7 in regular head waves (λ/L = 1 to 2.5) for added resistance and 2-DOF motion responses. The turbulent flow is simulated by the unsteady RANS method with the Realizable Two-Layer k-ε scheme. The calm water is represented by the flat VOF (Volume of Fluid) wave, while the incident long waves are represented by the fifth-order Stokes wave. The residual resistance of the Double-M craft is improved by 2.45% compared to that of the Delft 372 catamaran. In the case of maximum improvement (at λ/L = 1.50), the relative added resistance of the Double-M craft is 10.34% lower than the Delft 372 catamaran; moreover, the heave and pitch motion responses were 72.5% and 35.5% less, respectively.

Experimental Study on Seakeeping Performance of a Catamaran with Asymmetric Demi-Hulls

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
S. Ikezoe ◽  
N. Hirata ◽  
H. Yasukawa
Keyword(s):  
Experimental Study ◽  
Ship Motion ◽  
Added Resistance ◽  
Scaled Model ◽  
Seakeeping Performance ◽  
Head Waves ◽  
Lateral Space ◽  
Design Speed ◽  
Resistance Performance ◽  
Regular Head Waves

To capture the seakeeping performance of a catamaran with asymmetric demi-hulls, tank tests were carried out in regular head waves using a scaled model with 2.036 m in length. The lateral space between the demi-hulls was changed in the tests as W/B=2.55, 2.90 and 3.25, where W denotes breadth overall and B the breadth of the demi-hull. Also, two models with different water lines of inside flat and outside round (IF-type) and of outside flat and inside round (OF-type) were used. OF-type is superior to IF-type in both ship motion and added resistance performances in waves at the design speed. In IF-type series, the smallest clearance, W/B=2.55 is the best in the added resistance performance.

Study of Wave Added Resistance on Wigley Ship

2013 ◽  
Vol 468 ◽  
pp. 105-109
Author(s):  
Tao Sun ◽  
Ming Hui Yuan ◽  
Wei Wang ◽  
Nan Ye
Keyword(s):  
Total Resistance ◽  
Added Resistance ◽  
Ship Model ◽  
Seakeeping Performance ◽  
Head Waves ◽  
Free Model ◽  
Calm Water ◽  
Significant Research ◽  
Energy Consuming ◽  
Hydrodynamic Potential

Global warming is becoming a serious problem nowadays. The emissions of greenhouse gas from vessels draw great attentions. As a significant research part of vessel seakeeping performance, resistance capability exert pretty effect on energy consuming. A Wigley ship model is set as the object to compute constraint and free model in calm water and head waves on resistance and hydrodynamic potential coefficients by STAR-CCM. Differences are discussed between both models. Effects on calculation of hydrostatic resistance ignoring trim and heave are revealed .Wave added resistance of free model is computed and compared at different amplitudes and wavelengths. How trim and heave matter the computed results are discussed. So does how wavelength and amplitudes influence total resistance is considered.

Experiments and Computations for KCS Added Resistance for Variable Heading

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.

Evaluation of a Small and Fast Planing Boat’s Seakeeping Performance at the Design Stage

2015 ◽  
Author(s):  
Dong Jin Kim ◽  
Sun Young Kim
Keyword(s):  
Model Tests ◽  
Full Scale ◽  
Scale Model ◽  
Design Stage ◽  
Small Scale ◽  
Irregular Wave ◽  
Seakeeping Performance ◽  
Head Waves ◽  
Scale Ratio ◽  
Free Running

Seakeeping performance of a planing boat should be sufficiently considered and evaluated at the design stage for its safe running in rough seas. Model tests in seakeeping model basins are often performed to predict the performance of full-scale planing boats. But, there are many limitations of tank size and wave maker capacity, in particular, for fast small planing boats due to small scale ratio and high Froude numbers of their scale models. In this research, scale model tests are tried in various test conditions, and results are summarized and analyzed to predict a 3 ton-class fast small planing boats designed. In a long and narrow tank, towing tests for a bare hull model are performed with regular head waves and long crested irregular head waves. Motion RAOs are derived from irregular wave tests, and they are in good agreements with RAOs in regular waves. Next, model ships with one water-jet propulsion system are built, and free running model tests are performed in ocean basins. Wave conditions such as significant heights, modal periods, and directions are varied for the free running tests. Motion RMS values, and RAOs are obtained through statistical approaches. They are compared with the results in captive tests for the bare hull model, and are used to predict the full-scale boat performances.

Unsteady Viscous CFD Simulations of KCS Behaviour and Performance in Head Seas

2018 ◽  
Author(s):  
LiXiang Guo ◽  
JiaWei Yu ◽  
JiaJun Chen ◽  
KaiJun Jiang ◽  
DaKui Feng
Keyword(s):  
Degrees Of Freedom ◽  
Transfer Functions ◽  
Resistance Coefficient ◽  
Full Scale ◽  
Body Motion ◽  
Ship Motions ◽  
Added Resistance ◽  
Viscous Effects ◽  
Head Waves ◽  
And Performance

It is critical to be able to estimate a ship’s response to waves, since the added resistance and loss of speed may cause delays or course alterations, with consequent financial repercussions. Traditional methods for the study of ship motions are based on potential flow theory without viscous effects. Results of scaling model are used to predict full-scale of response to waves. Scale effect results in differences between the full-scale prediction and reality. The key objective of this study is to perform a fully nonlinear unsteady RANS simulation to predict the ship motions and added resistance of a full-scale KRISO Container Ship. The analyses are performed at design speeds in head waves, using in house computational fluid dynamics (CFD) to solve RANS equation coupled with two degrees of freedom (2DOF) solid body motion equations including heave and pitch. RANS equations are solved by finite difference method and PISO arithmetic. Computations have used structured grid with overset technology. Simulation results show that the total resistance coefficient in calm water at service speed is predicted by 4 .68% error compared to the related towing tank results. The ship motions demonstrated that the current in house CFD model predicts the heave and pitch transfer functions within a reasonable range of the EFD data, respectively.

scholarly journals Effects of diffraction in regular head waves on added resistance and wake using CFD

2019 ◽  
Vol 11 (2) ◽  
pp. 736-749 ◽  
Author(s):  
Cheol-Min Lee ◽  
Sung-Chul Park ◽  
Jin-Won Yu ◽  
Jung-Eun Choi ◽  
Inwon Lee
Keyword(s):  
Added Resistance ◽  
Head Waves ◽  
Regular Head Waves

Unsteady Numerical Simulation of the Behavior of a Ship Moving in Head Sea

2019 ◽  
Author(s):  
Adrian Lungu
Keyword(s):  
Free Surface Flow ◽  
Surface Flow ◽  
Incoming Wave ◽  
Grid Convergence ◽  
Head Waves ◽  
Calm Water ◽  
Unsteady Numerical Simulation ◽  
Resistance Coefficients ◽  
Regular Head Waves ◽  
Numerical Approaches

Abstract The paper follows a previous work of the author that dealt with ship resistance and self-propulsion numerical investigations, proposing a series of numerical simulations performed to assess the seakeeping performances of the KCS model which moves in regular head waves. Various simulations of the free-surface flow around the hull equipped with rudder moving either in calm water or in heading waves are proposed. For the calm water case, in which a series of six Fr numbers is considered, verification and validation based on the grid convergence tests are performed. Then, a series of five different simulations for various incoming wave characteristics are presented and discussed in every detail. Comparisons with the experimental data [1], [2] are provided aimed at validating the numerical approaches in terms of the total resistance coefficients as well as the heave and pitch motions characteristics. Several remarks will conclude the findings of the present work.

Numerical Analysis and Experimental Validation of Added Resistance on Ship in Waves

2019 ◽  
Vol 63 (4) ◽  
pp. 268-282
Author(s):  
Yonghwan Kim ◽  
Dong-Min Park ◽  
Jae-Hoon Lee ◽  
Jaehoon Lee ◽  
Byung-Soo Kim ◽  
...  
Keyword(s):  
Momentum Conservation ◽  
Numerical Results ◽  
Added Resistance ◽  
Irregular Wave ◽  
Numerical Studies ◽  
Motion Responses ◽  
Calm Water ◽  
National University ◽  
The Difference ◽  
Seoul National University

In this study, the added resistance of a liquefied natural gas carrier (LNGC) in the presence of waves is studied experimentally and numerically.The ship model is an LNGC designed by Samsung Heavy Industries (SHI). Experiments on ship motion responses and added resistance under head sea conditions were conducted at the Seoul National University and SHI. The influences of the experimental methods (captive and self-propulsion methods), incident wave amplitude, and regular and irregular wave conditions on the added resistance are evaluated using the same model ship set at different scales. In the numerical studies, the motion responses and added resistance are obtained using three methods—the strip method by adopting momentum conservation; Rankine panel method using pressure integration; and computational fluid dynamics method, using the difference in the resistances in waves and calm water. The experimental and numerical results under various conditions are compared, and the characteristics of the experimental and numerical results are discussed.

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