A Rankine Panel Method for Added Resistance of Ships in Waves

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Heinrich Söding ◽  
Vladimir Shigunov ◽  
Thomas E. Schellin ◽  
Ould el Moctar
Keyword(s):  
Degrees Of Freedom ◽  
Periodic Wave ◽  
Panel Method ◽  
Navier Stokes ◽  
Ship Motions ◽  
Added Resistance ◽  
Rankine Panel Method ◽  
Head Waves ◽  
Wigley Hull ◽  
The Time Domain

A new Rankine panel method and an extended Reynolds-Averaged Navier–Stokes (RANS) solver were employed to predict added resistance in head waves at different Froude numbers of a Wigley hull, a large tanker, and a modern containership. The frequency domain panel method, using Rankine sources as basic flow potentials, accounts for the interaction of the linear periodic wave-induced flow with the nonlinear steady flow caused by the ship's forward speed in calm water, including nonlinear free surface conditions and dynamic squat. Added resistance in waves is obtained by the pressure integration method. The time domain RANS solver, based on a finite volume method, is extended to solve the nonlinear equations of the rigid body six-degrees-of-freedom ship motions. The favorable comparison of the panel and RANS predictions demonstrated that the Rankine method is suitable to efficiently obtain reliable predictions of added resistance of ships in waves. Comparable model test predictions correlated less favorably, although the overall agreement was felt to be acceptable, considering the difficulties associated with the procedures to obtain accurate measurements.

A Rankine Panel Method for Added Resistance of Ships in Waves

2012 ◽  
Author(s):  
Heinrich Söding ◽  
Vladimir Shigunov ◽  
Thomas E. Schellin ◽  
Ould el Moctar
Keyword(s):  
Degrees Of Freedom ◽  
Periodic Wave ◽  
Panel Method ◽  
Ship Motions ◽  
Added Resistance ◽  
Rankine Panel Method ◽  
Head Waves ◽  
Calm Water ◽  
Wigley Hull ◽  
The Time Domain

A new Rankine panel method and an extended RANS solver were employed to predict added resistance in head waves at different Froude numbers of a Wigley hull, a large tanker, and a modern containership. The frequency domain panel method, using Rankine sources as basic flow potentials, accounts for the interaction of the linear periodic wave-induced flow with the nonlinear steady flow caused by the ship’s forward speed in calm water, including nonlinear free surface conditions and dynamic squat. Added resistance in waves is obtained by pressure integration method. The time domain RANS solver, based on a finite volume method, is extended to solve the nonlinear equations of the rigid body six-degrees-of-freedom ship motions. The favorable comparison of panel and RANS predictions demonstrated that the Rankine method is suitable to efficiently obtain reliable predictions of added resistance of ships in waves. Comparable model test predictions correlated less favorably although overall agreement was felt to be acceptable, considering the difficulties associated with procedures to obtain accurate measurements.

NUMERICAL PREDICTION OF VERTICAL SHIP MOTIONS AND ADDED RESISTANCE

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.

Numerical Prediction of Vertical Ship Motions and Added Resistance

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.

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.

Numerical Prediction of the Added Resistance of Ships in Waves

2014 ◽  
Author(s):  
Jens Ley ◽  
Sebastian Sigmund ◽  
Ould el Moctar
Keyword(s):  
Degrees Of Freedom ◽  
Stokes Equations ◽  
Linear Equations ◽  
Computational Effort ◽  
Navier Stokes ◽  
Ship Motions ◽  
Added Resistance ◽  
Field Methods ◽  
Rans Equations ◽  
Added Resistance In Waves

The added resistance in waves is computed for different ship types using two different Reynolds-Averaged Navier-Stokes Equations (RANSE) solvers, namely Comet and interFoam (OpenFOAM). Hence, the RANS equations are implicitly coupled with the non-linear equations of motions for six degrees of freedom and the solvers are extended by algorithms for mesh morphing to account for ship motions. The computational effort for these simulations is high compared to potential flow based simulations, especially for short waves. However, to understand the physics related to added resistance of ships and to investigate influencing parameters, field methods based on RANS equations may be suitable. The prediction of the added resistance in waves consists of two steps; the computations of the calm water resistance and the total resistance in waves. The discretisation errors as well as the influence of the surge motions on the added resistance are investigated. Further, the added resistance is decomposed in diffraction and radiation problems as it is commonly done in potential theory.

Study of Wave Added Resistance and Motions of KCS in Waves With Different Wave Lengths

2019 ◽  
Author(s):  
Hao Guo ◽  
Decheng Wan
Keyword(s):  
Navier Stokes ◽  
Head Wave ◽  
Ship Motions ◽  
Added Resistance ◽  
Head Waves ◽  
Wide Range ◽  
Stokes Waves ◽  
The Relationship ◽  
Nonlinear Behaviors ◽  
Regular Head Waves

Abstract Estimating added resistance and motions of a ship in waves are essential to predict fuel consumption and speed loss. The added resistance and motions of the 3600 TEU KRISO container ship (KCS) in regular head waves under different wavelengths are investigated using Reynolds-Averaged Navier-Stokes (RANS) method. Volume of Fluid (VOF) method is applied to capture the free surface. The in-house computational fluid dynamics solver, naoe-FOAM-SJTU, is used to compute the added resistance and motions of KCS in regular head waves. Firstly, the first-order Stokes waves in deep water are adopted and generated in naoe-FOAM-SJTU as a numerical wave tank. Secondly, it is presented that the KCS with a Froude number of 0.261 advances in these waves. Regular wave conditions with a wide range of wavelength (0.65 < λ/L < 1.95) are considered. The variations of resistance, pitch and heave show good agreement with experimental results. To investigate nonlinear behaviors of predicted results, Fast Fourier Transform (FFT) is applied to analyze the results of resistance, heave and pitch with in head wave (μ = 180°). KCS with and without motions is also compared to investigate the relationship between components of resistance and wavelengths. The results of added resistances show that the added resistance of KCS is mainly induced by ship diffraction in short waves. The wave diffraction is not affected by wave frequency. In addition, CFD can accurately calculate the problem on added resistance and ship motions.

Numerical and Experimental Study of the Parametric Rolling of a Fishing Vessel in Regular Head Waves

2013 ◽  
Vol 155 (A4) ◽  
Keyword(s):  
Degrees Of Freedom ◽  
Assessment Tool ◽  
Prediction Method ◽  
Theory Model ◽  
Design Stage ◽  
Ship Motions ◽  
Fishing Vessel ◽  
Parametric Rolling ◽  
Strip Theory ◽  
Head Waves

The dynamic behaviour of a fishing vessel in waves is studied in order to reveal its parametric rolling characteristics. This paper presents experimental and numerical results in longitudinal regular waves. The experimental results are compared against the results of a time-domain non-linear strip theory model of ship motions in six degrees-of-freedom. These results contribute to the validation of the parametric rolling prediction method, so that it can be used as an assessment tool to evaluate both the susceptibility and severity of occurrence of parametric rolling at the early design stage of these types of vessels.

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