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.

Prediction of Resistance and Self-Propulsion Characteristics of a Full-Scale Naval Ship by CFD-Based GEOSIM Method

2020 ◽  
pp. 1-16 ◽  
Author(s):  
Cihad Delen ◽  
Ugur Can ◽  
Sakir Bal
Keyword(s):  
Degrees Of Freedom ◽  
Full Scale ◽  
The Self ◽  
Body Motion ◽  
Ship Motions ◽  
Naval Research ◽  
Propulsion Performance ◽  
Office Of Naval Research ◽  
Naval Ship ◽  
Computational Fluid Dynamics Cfd

Resistance and self-propulsion characteristics of a naval ship at full scale have been investigated by using Telfer’s GEOmetrically SIMilar (GEOSIM) method based on the computational fluid dynamics (CFD) approach. For this purpose, first, the resistance forces of the Office of Naval Research Tumblehome (ONRT) hull have been computed at different three model scales by using the overset mesh technique. The full-scale resistance and nominal wake fraction of the ONRT hull have been estimated by using Telfer’s GEOSIM method. Resistance and nominal wake fraction have then been compared with those of CFD at full scale. Later, the self-propulsion characteristics of the ONRT hull have been examined using Telfer’s GEOSIM method based on the CFD approach. Self-propulsion factors at the full-scale hull have been predicted by using the SST k-ω turbulence model to involve 2-degrees of freedom ship motions (heave and pitch). Rotational motion of the propeller has also been simulated by using the rigid body motion technique. The results calculated by Telfer’s GEOSIM method and the 1978 International Towing Tank Conference (ITTC) extrapolation technique have been compared with each other and discussed with those of the CFD approach at full scale. It was found that the full-scale results (both resistance and self-propulsion factors) predicted by Telfer’s GEOSIM method are closer to those of the CFD approach than those of the 1978 ITTC technique. It can be noted that Telfer’s GEOSIM method is fast, robust, and reliable and can be used as an alternative to the 1978 ITTC method for predicting the self-propulsion performance of a full-scale ship.

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.

Scale Effect Studies on Hydrodynamic Performance for DTMB 5415 Using CFD

2018 ◽  
Author(s):  
Heng Zhang ◽  
Hang Zhang ◽  
Xuanshu Chen ◽  
Hao Liu ◽  
Xianzhou Wang
Keyword(s):  
Degrees Of Freedom ◽  
Wave Pattern ◽  
Resistance Coefficient ◽  
Body Motion ◽  
Hydrodynamic Performance ◽  
Scale Model ◽  
Ship Motions ◽  
Calm Water ◽  
Unsteady Rans ◽  
Scale Design

Making CFD with the capability of predicting ship scale design performance, rather than relying on scale model tests will help reduce design costs and provide a greater opportunity to develop more energy efficient ship designs. The key objective of this paper is to perform a fully nonlinear unsteady RANS simulation to predict the ship motions and resistance of a full scale DTMB 5415 ship model. The analyses are performed at design speeds, at a certain Fr number, using in-house computational fluid dynamics (CFD) to solve RANS equation coupled with six degrees of freedom (6DOF) solid body motion equations. RANS equations are solved by finite difference method and PISO arithmetic. Computations have been made using structured grid with overset technology. Simulation results shown that the total resistance coefficient in calm water at service speed is predicted by 2.36% error compared to the related towing tank results. The ship resistance for different scale demonstrated that the current in-house CFD model could predict the resistance in a reasonable range of the EFD data. The comparison of flow field for wave pattern for different scale model were analyzed and discussed.

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.

Scaling of the Hydroelastic Response of Flexible Lifting Bodies in Transitional and Turbulent Flows

2013 ◽  
Author(s):  
Antoine Ducoin ◽  
Yin Lu Young
Keyword(s):  
Turbulent Flows ◽  
Degrees Of Freedom ◽  
Experimental Studies ◽  
Full Scale ◽  
Stress Distributions ◽  
Viscous Effects ◽  
Scaling Methods ◽  
Fluid Properties ◽  
Computational Fluid Dynamics Cfd ◽  
Hydroelastic Response

The objective of this research is to derive and validate scaling relationships for flexible lifting bodies in transitional and turbulent flows. The motivation is to help the design and interpretation of reduced-scale experimental studies of flexible hydrofoils, with focus on the influence of viscous effects on the hydroelastic response. The numerical method is based on a previous validated viscous FSI solver presented in [1]. It is based on the coupling between a commercial Computational Fluid Dynamics (CFD) solver, CFX, and a simple two-degrees-of-freedom (2-DOF) system that simulates the free tip section displacement of a cantilevered, rectangular hydrofoil. To validate the scaling relations, sample numerical results are shown for three geometrically similar models: full scale, 1/2 scale and 1/10 scale. On the fluid side, although the effects of gravity and compressibility are assumed to be negligible, three different methods of scaling the velocity are considered: Reynolds scaling, Froude scaling, and Mach scaling. The three scaling methods produce different velocity scales when the fluid properties and gravitational constant are the same between the model and prototype, which will lead to different scaling for the material properties. The results suggest that by applying Mach scaling (which does not mean the flow is compressible, but simply requires the relative inflow velocity and fluid properties to be the same between the model and the prototype) and Re ≥ 2 × 106, the same material as the full scale could be used, which will lead to similar stress distributions, in addition to similar strains, and hence similar hydroelastic response and failure mechanisms. However, if Re ≤ 2 × 106 and Mach scale is used, a viscous correction is required to properly extrapolate the experimental results to full-scale.

Numerical Simulation of Damaged Ship’s Motion in Beam Waves

2019 ◽  
Author(s):  
Qing Wang ◽  
Xuanshu Chen ◽  
Liwei Liu ◽  
Xianzhou Wang ◽  
MingJing Liu
Keyword(s):  
Degrees Of Freedom ◽  
Body Motion ◽  
Ship Motions ◽  
Rans Equations ◽  
Six Degrees Of Freedom ◽  
Calm Water ◽  
Unsteady Simulation ◽  
Ship Hydrodynamic ◽  
Physical Phenomena ◽  
Damaged Ship

Abstract The dangerous situation caused by the breakage of the ship will pose a serious threat to crew and ship safety. If the ship’s liquid cargo or fuel leaks, it will cause serious damage to the marine environment. If damage occurs accompanied by roll and other motions, it may cause more dangerous consequences. It is an important issue to study the damaged ship in time-domain. In this paper, the motions of the damaged DTMB 5512 in calm water and regular beam waves are studied numerically. The ship motions are analyzed through CFD methods, which are acknowledged as a reliable approach to simulate and analyze these complex physical phenomena. An in-house CFD (computational fluid dynamics) code HUST-Ship (Hydrodynamic Unsteady Simulation Technology for Ship) is used for solving RANS equations coupled with six degrees of freedom (6DOF) solid body motion equations. RANS equations discretized by finite difference method and solved by PISO algorithm. Level set was used for free surface simulation. The dynamic behavior of model was observed in both intact and damaged condition. The heave, roll and pitch amplitudes of the damaged ship were studied in calm water and beam wave of three wavelengths.

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.

Sign in / Sign up

Export Citation Format

Share Document