Turning Circle Maneuver Research Articles

Assessing the influence of sudden propulsion loss on a ship's manoeuvrability in various wave heights utilizing CFD

The prevalence of ship propulsion failure remains a significant concern at sea, posing a recurring risk to maritime safety. As a ship's ability to manoeuvre heavily relies on its propulsive power generated by a rotating propeller, any loss in propulsion can lead to potential hazards such as collisions, contacts, or groundings, particularly in a real seaway. Therefore, accurately assessing the manoeuvring capabilities of ships experiencing propulsion failure is crucial for ensuring navigation safety. This paper aims to examine the impacts of sudden propulsion loss on the manoeuvring capability of the KCS (KRISO Container Ship) model under different wave heights, utilizing URANS (Unsteady Reynolds-Averaged Navier-Stokes) simulations. Through a series of case studies comparing ship performances under normal conditions versus propulsion loss scenarios, particularly during turning circle manoeuvres in different wave height conditions, the study sheds light on the significant impact of propulsion failure on ship manoeuvrability. When examining the ship's turning performance under identical wave heights, it became evident that the ship's advance increased in instances of propulsion loss compared to normal operational conditions. Specifically, at a wave height of 2.4 m, the ship's advance increased by 23% during propulsion failure. Similarly, at wave heights of 3.6 m, 4.8 m, and 6.0 m, the increases were 19%, 17%, and 12%, respectively. In calm water, there was a 24% increase in advance. Notably, at a wave height of 7.2 m, the ship failed to complete a 90° turn, making it impossible to determine the ship's advance under these conditions. The findings underscore the critical importance of sufficient propulsion power for safe vessel operation. This research not only provides valuable insights for navigators into ship manoeuvring under propulsion failure but also contributes to the development of contingency measures, especially pertinent for autonomous vehicles encountering similar propulsion challenges.

Numerical Simulations of a Ship’s Maneuverability in Shallow Water

It is necessary to maintain maneuverability for ship navigation in shallow water, such as channels, ports and other confined waters. In this study, a turning circle maneuver with 35° rudder deflection and a 20/5 zigzag maneuver for KVLCC2 in shallow waters are tested numerically to directly predict the maneuverability of the ship in shallow water. A viscous in-house CFD solver is applied with the dynamic overset grid approach. The impacts of the water depth on the ship’s maneuverability in terms of turning and zigzag competence are evaluated, and the underlying mechanism is analyzed. The numerical method is validated by comparing it with experimental data on the turning indices, which shows good agreement. It is demonstrated that the turning capability become worse with a smaller depth–draft ratio, thus resulting in a lower yaw rate and a greater steady turning diameter. However, the drift angle and lateral speed are reduced with a smaller depth–draft ratio for zigzag maneuvers, but the overshoot angle and turn lag vary with the water depth non-monotonically.

Prediction of horizontal and vertical turning maneuvers of a generic submarine model by closed-form solutions and CFD

Turning maneuvering performance of a generic submarine in both the horizontal and vertical planes is investigated using closed-form (analytical) solutions and the Computational Fluid Dynamics (CFD) method. The aim is to provide a simple yet improvable method throughout the design phase of an underwater vehicle. Both the turning circle maneuver in the horizontal plane and the rising maneuver in the vertical plane are performed. Vehicle trajectories are obtained using closed-form solutions and a linearized maneuvering model with a limited set of hydrodynamic coefficients computed from the CFD model. The derivation of the closed-form solution is based on the basic mechanical principles of steady circular motion, while the hydrodynamic coefficients are determined via steady CFD simulations using a single grid topology. The steady turning diameter serves as the figure of merit in a turning circle maneuver. For the rising maneuver, trajectories predicted by both methods are directly compared. The methods are found to be in good agreement for both maneuvers. Maneuvering predictions made with the linear coefficient set are also open to development. As the design of the submarine evolve, nonlinear and coupled effects can be included in the mathematical model by incorporating related hydrodynamic coefficients to obtain more accurate results.

Virtual PMM captive tests using OpenFOAM to estimate hydrodynamic derivatives and vessel maneuverability

This study reveals the significance of hydrodynamic derivatives derived at the different Froud number (Fr) in accurately predicting of a vessel's turning-circle maneuvers through solving the maneuvering modeling group (MMG) model. The computed turning-circle diameter showed a good agreement with the model test results, with less than 4% difference observed when using the hydrodynamic derivatives derived at Fr = 0.201. However, at Fr = 0.26, a significant difference was observed, which could be attributed to the use of lower values of maximum sway amplitude ymax and maximum yaw rate rmax′. The hydrodynamic characteristics of a maneuvering vessel may not be fully reflected, with the high displacement of the straight surging motion dominating the results. In this study, a set of virtual planar motion mechanism (PMM) captive tests is numerically conducted on a bare container ship hull model using an open-source code OpenFOAM. The virtual PMM captive test cases involve different maximum sway amplitude, maximum yaw rates, and Fr, achieved by varying sway amplitudes, heading angles, and the carriage speeds, respectively. The obtained numerical results are reconstructed as Fourier series (FS) equations to derive hydrodynamic derivatives employing the single run (SR) method. A system-based method is adopted to predict vessel's turning-circle maneuverability in calm water by employing the MMG mathematical model.

Mathematical modeling of shallow water effects on ship maneuvering

An Abkowitz-type model was extended to improve the prediction of maneuvering dynamics of inland ships in deep and shallow waters. First, additional coupled rudder and speed related hydrodynamic derivatives were added to better capture hydrodynamic forces and moments. Second, higher order drift related hydrodynamic derivatives were implemented to more reliably predict longitudinal forces. Steady RANS-based captive model tests were performed to estimate speed-dependent hydrodynamic derivatives. Unsteady captive model tests, based on applying a novel Euler equations based numerical approach, were carried out to determine acceleration-dependent zero-frequency hydrodynamic derivatives. Executed were propulsion tests, rudder tests, coupled propulsion and rudder tests, rotating arm tests, drift tests, and coupled rotating arm and drift tests, all at five water depths to draft ratios of 1.43, 1.79, 2.00, 4.00, and 8.00. Tests at the ratio 1.79 were validated against physical captive model tests, and regression analyses estimated the hydrodynamic derivatives. At each water depth, a 45 deg turning circle test, a 35/10 zigzag test, and a 45/110 evasive action test were carried out. Turning circle maneuvers were significantly influenced by shallow water. Compared to deep water, in shallow water the tactical diameter increased from 1.6L to 2.6L, and the drift angle decreased from 21 deg to about 4 deg. Compared to turning circles maneuvers, effects on the zigzag and evasive action maneuvers were relatively small in shallow water. Drift angles and yaw rates in the simulated 45 deg turning circle and a 35/5 zigzag tests agreed favorably with full-scale trials of a similar ship; however, scale effects and the slightly different hull shapes led to different speed losses.

A study on interaction among hull, diesel engine and propellers of a twin-screw ship during turning circle maneuver

A marine propulsion plant will experience power fluctuations during ship maneuvers. In the turning circle maneuver, the propulsive load increases significantly, and the power required by the two shafts of a twin-screw ship may be completely inconsistent. To protect the propulsion plant, the interaction between the engine and the propellers should be studied in depth. In this paper, the twin-screw ONRT ship and the 16PA6-STC diesel engine are selected as the study objects. A series of captive model tests are simulated by using CFD method to obtain the hydrodynamic derivatives and hull-propeller-rudder interaction coefficients in the MMG model. The effective wake fraction is computed under the maneuvering conditions. Turning circle maneuver of the ship is predicted by using the established MMG model, and the predicted ship maneuvering characteristics show good agreement with the available experimental results, which verifies the CFD-based modeling method. Finally, a dynamic model of hull-engine-propeller system is established on the simulation platform for evaluating the operating characteristics of propulsion plant. The propeller loads are predicted and the interaction among hull, engine and propellers is investigated. This study helps to provide a deeper insight into the engine operation behaviors during turning circle maneuver of a ship.

Prediction of the maneuvering behavior of a containership in a seaway

This study investigated the turning maneuver performance of a containership in regular waves using a two-time scale formulation. This article also presents a ship motion program, coupled with a 3-degree of freedom (3-DOF) maneuvering solver, whereby the seakeeping problem is solved with the forward speed considered in the computations. Captive tests were simulated in a computational fluid dynamics (CFD) environment to obtain the maneuvering derivatives. A near-field analysis was performed to obtain the effective wave force, which was the second-order mean drift force in this analysis. The proposed method was used to estimate the turning circle maneuver performance of the S-175 containership in both calm water and waves of different wavelengths. Ultimately, the simulation results showed high consistency with experimental data.

Nonparametric modeling of ship maneuvering motion in waves based on Gaussian process regression

A robust and easy-to-operate method based on Gaussian process regression (GPR) is proposed for nonparametric modeling of ship maneuvering in waves. The wave parameters that are difficult to measure are not needed when identifying the dynamic model. In order to extract the wave effect from the ship motion data, the black-box model is modified relative to that used for calm water case. Taking the KCS container ship and the S-175 container ship as study objects, the nonparametric models based on GPR are identified by utilizing the experimental data of turning circle maneuver of KCS model and zigzag maneuvers of S-175 model in regular waves. Using the identified nonparametric models, turning circle maneuver of KCS model and zigzag maneuvers of S-175 model in regular waves are predicted, and the prediction results are compared with the model test data to verify the proposed method of nonparametric modeling and to evaluate the performances of the identified nonparametric models. It shows that the trajectory of turning circle maneuver and the heading angle of zigzag maneuvers are well predicted, indicating that the nonparametric model based on GPR with the modified black-box model can predict the maneuvering motion in regular waves accurately.

A systematic investigation on the manoeuvring performance of a ship performing low-speed manoeuvres in adverse weather conditions using CFD

The International Maritime Organisation (IMO) requirements for the control of greenhouse gas (GHG) emissions of shipping have raised interest in ship manoeuvrability in adverse weather conditions when compliance is accomplished simply by reducing the main engine power. In response, the IMO has adopted the guidelines for determining minimum propulsion power to maintain the manoeuvrability of ships in adverse conditions. In the present paper, a systematic investigation on the manoeuvrability of a ship with different low advance speeds in adverse weather conditions was conducted by means of an unsteady Reynolds-Averaged Navier-Stokes solver. The numerical results demonstrated the contribution of low advance speeds to the course-keeping and turning circle manoeuvre, providing a practical insight into the manoeuvring performance of a ship with minimum propulsion power in adverse weather conditions. For the course-keeping control, the ship experienced more aggressive steering as the propeller revolution decreased in the oblique waves, while it appeared that the difference in the rudder deflection according to the change in the propeller speed in the head, beam, and following waves is negligible. The difficulty of the low speed turning manoeuvre was clearly noted when the direction of the incident wave was opposite to the direction towards which the ship intended to turn. It is believed that this paper can also be impactful in improving the guidelines of minimum powering of ships for safe navigation in adverse weather conditions.

CFD and system-based investigation on the turning maneuver of a twin-screw ship considering hull-engine-propeller interaction

Ship maneuver is a dynamic process accompanied by strong interaction among hull, engine, and propeller, and the interaction phenomenon is more complicated for twin-screw ships. In this paper, numerical investigation on the turning maneuver of a twin-screw ship considering hull-engine-propeller interaction is carried out by using CFD and system-based methods. Taking the twin-screw ship ONRT model as the study object, a series of captive model tests are simulated by using RANS method. Based on the computed global loads on the propellers and the corresponding flow field details, the hydrodynamic characteristics of the propellers operating under the maneuvering conditions are analyzed. The effective wake fraction is computed and the mathematical model of propeller performance under the maneuvering conditions is obtained through data fitting. Based on the established mathematical model, the turning circle maneuver considering hull-engine-propeller interaction is simulated. Three control strategies of main engine, i.e., constant RPM, constant torque, and constant power, are considered. The effects of the control strategies on the turning motion and the propulsive loads during turning motion are explored. This study is useful to provide a deeper insight into the ship maneuvering behaviors and the propeller characteristics during maneuvering motion under the influence of hull-engine-propeller interaction.

Nonlinear URANS model for evaluating course keeping and turning capabilities of a vessel with propulsion system failure in waves

The loss of ship propulsion has been reported to be the most frequent cause of accidents at sea over the last few years. The loss of propulsive power has a notable effect on the behaviour of a ship during ship manoeuvring, and hence the manoeuvrability of ships suffering from propulsion loss should be accurately estimated for navigation safety. The aim of this study is to evaluate the effects of a propulsion failure on the manoeuvrability of the KRISO Container Ship (KCS) using a fully nonlinear URANS model, which is capable of resolving complex fluid-structure interactions with high accuracy. A series of case studies were carried out to compare the ship performances of both the normal and propulsion loss condition, especially for the course keeping and turning circle manoeuvres. The results explicitly revealed that the propulsion failure has a strong influence on the ship manoeuvrability, implying the importance of sufficient propulsion power when vessels are underway. The key findings obtained from this study are believed to provide navigators with a practical insight into ship manoeuvrability under the propulsion failure condition as well as contribute to developing standards for navigational safety in waves.

Unsteady RANS CFD simulations of ship manoeuvrability and course keeping control under various wave height conditions

Ships encounter different wave heights in real sea states. Various wave heights can lead to substantial changes in the behaviour of a ship during manoeuvring, and hence a ship's manoeuvrability in waves should be accurately evaluated to ensure navigational safety at sea. The aim of this study is to estimate wave height effects on the manoeuvring behaviour of the benchmarking KRISO Container Ship (KCS) model by performing a fully nonlinear unsteady RANS simulation. Three types of manoeuvres were simulated with the free-running KCS model appended with an actuator disk and a moving semi-balanced horn rudder using a dynamic overset technique: self-propulsion, course keeping control, and turning circle manoeuvres. Manoeuvring analyses were carried out in the bow quartering waves of a range of wave heights for constant wave length, as coupled with the fifth-order Stokes wave model. In order to control the rudder deflection based on manoeuvre mechanisms, a feedback controller was embedded in the present CFD model. The results clearly revealed that wave heights have a strong effect on the manoeuvring behaviour of the KCS, including ship's speeds, seakeeping behaviour, and critical turning indices through comparative analyses under different wave height conditions. One important finding is the standard manoeuvring parameters in waves, which would help navigation officers in decision-making for manoeuvring actions in waves.

Numerical investigation of interaction between propulsion system behaviour and manoeuvrability of a large containership

In actual operation process of a ship, the engine-propeller-hull is an integrated system with internal coupling effects, and thus there is a close interaction between the diesel engine propulsion system operation conditions and the ship manoeuvring motions. The propulsion system can experience large power fluctuation during manoeuvring, with considerable torque increase with regard to the stabilized value in straight course. However, the diesel engine propulsion system behaviour and ship manoeuvrability are usually studied separately as they are considered to belong to different disciplines. Thus, it is difficult to reflect the actual operating characteristics of the propulsion system and ship manoeuvring motion under coupled conditions in actual operation. To investigate the interaction between the propulsion system behaviour and the manoeuvrability of a large containership, this paper proposed a multi-disciplinary ship mobility model capable of coupling the marine diesel engine model and the ship manoeuvring model. In the engine model, the mean value modelling approach was adopted to simulate the two-stroke marine diesel engine considering the fact that it can capture the performance of the engine sub-systems including scavenging receiver, exhaust gas receiver, turbocharger, etc. In the manoeuvring model, the MMG-based method was used to simulate the ship manoeuvring motion with three degrees-of-freedom. The engine model and manoeuvring model were coupled through the propeller model that transferring propeller speed and torque between the two models. The coupled model was validated against the engine shop test data and the sea trial results. By applying this coupled model, a series of simulations of turning circle manoeuvres under various scenarios were performed. The simulation results presented the dynamic response of engine internal sub-systems during turning circle manoeuvring, explained the effect of the torque limiter on engine performance and ship manoeuvring motion, and analyse the influence of different propulsion system control strategies on the ship turning circle manoeuvrability. Although the presented case study has been validated on a specific ship, most of the discussed models have a general application.

Nonparametric modeling of ship maneuvering motion based on Gaussian process regression optimized by genetic algorithm

A novel method, Gaussian process regression optimized by genetic algorithm (GA-GPR), is proposed for nonparametric modeling of ship maneuvering motion. A genetic algorithm with adaptive crossover and mutation operations is introduced for adjustment and optimization of hyperparameters in the kernel function. The sliding time window method is adopted to update the training samples to improve the adaptability of the model. Taking the Mariner vessel and the container ship KCS as study objects, the simulation data and the real measured data provided by SIMMAN 2020 workshop are employed to evaluate the proposed method. The prediction results of the proposed method and the traditional Gaussian process regression are compared and validated against available experimental data of zigzag and turning circle maneuvers. It shows that the proposed method has higher prediction accuracy and better generalization ability, indicating that the hyperparameters optimized by genetic algorithm make the model closer to the ship's dynamic characteristics.

Numerical evaluation of a ship's manoeuvrability and course keeping control under various wave conditions using CFD

It is critical to estimate the manoeuvring behaviours of ships in waves since it is closely associated with navigation safety at sea. This study aims to predict the wavelength effects on the ship manoeuvring behaviours using a Computational Fluid Dynamics (CFD) based technique which enables resolving the complex interactions between hull, rudder, and propeller in waves. An Unsteady Reynolds-Averaged Navier-Stokes (URANS) model of the well-known benchmarking KRISO Container Ship (KCS) was developed using the dynamic overset grid technique to simulate the ship motions and rudder deflection. To represent the effects of the propeller, the body force method using an infinite-blade actuator disk was used. The manoeuvring analyses were carried out in bow waves of wavelength-to-ship-length ratios varying between 0.7 and 2.0 for constant wave height. Two representative free-running manoeuvres were conducted, namely, course keeping control, and standard turning circle manoeuvres. The analyses revealed that the wavelength has a significant influence on the manoeuvring performance, especially for the approach speeds, ship motions, and manoeuvring indices. The key findings of this research will increase the understanding of ship manoeuvrability in waves and therefore help to enhance navigation safety at sea.

CFD Simulations of Self-Propulsion and Turning Circle Maneuver up to 90º of Ship in Waves

In the present work, a Reynolds-Averaged Navier-Stokes (RANS)-overset method is used to numerically investigate self-propulsion and turning circle maneuver in waves for a container ship. A computational fluid dynamics (CFD) solver naoe-FOAM-SJTU is used for the numerical computations of the fully appended Duisburg Test Case ship model. Overset grids are used to handle the motions of the ship hull appended with the propeller and the rudder. Open source toolbox waves2Foam is used to prevent wave reflection in the computational domain. The current numerical method is validated by comparing the ship speed in the self-propulsion case between CFD and Experimental Fluid Dynamics (EFD). Predicted ship 6-DOF motions, hydrodynamic forces, free surfaces, and inflow of the propeller are presented. The propulsion characteristic is mainly studied. Assuming the thrust identification method works even in unsteady conditions, the wake fraction and propulsion efficiency are discussed. The effect of orbital motion of water particle and ship motion on the propulsion performance are identified. In conclusion, the present RANS-overset method is a reliable approach to directly simulate self-propulsion and turning circle maneuver in waves.

Analysis of fretting inception for marine propeller by single blade loads measurement in realistic operating conditions. Straight ahead and turning circle maneuver

Controllable pitch propeller (CPP) is a versatile solution to fulfill high hydrodynamic efficiency and low environmental emissions for different operative scenario of a seagoing vessel because it allows the most suitable matching between the prime mover and the propulsor. In contrast, this configuration is a complex mechanical system and, therefore, it may be subjected to a wide range of failures related to the automation system of blade pitch variation, strength and fatigue life of the various mechanical components. This paper focuses on blade fretting, that is a small amplitude vibratory motion of the blade with respect to its lodging in the hub; this motion causes the wear between the contact surfaces, reducing the fatigue life of the material as well. The prediction of this phenomenon in realistic sailing conditions during the design stage is of utmost importance to prevent damages and failures during ship operations, by developing suitable control laws. The analysis is based on single blade loads measurements, obtained with a novel set–up installed on a free running maneuvering, self–propelled model of a twin screw ship. The experimental campaign was aimed to characterize single blade loads during different ship operations, with particular effort on maneuvering (standard and safety maneuvers) and motion in waves. This paper is focused on the straight ahead motions as well as steady and transient phases of the turning circle maneuver, performed at different rudder angles and speeds. The results show that the onset of fretting is sensitive to the wake evolution, and, hence, to the rudder angles; moreover, consistently to the asymmetric behavior of the propellers, fretting is differently triggered on the port and starboard propeller.

CFD study of ship stopping maneuver by overset grid technique

The crowded waterways and worse maneuverability of large ships could cause more collision accidents. Therefore, it is necessary to study stopping ability of ships to ensure the navigational safety. In this paper, the CFD solver naoe-FOAM-SJTU associated with dynamic overset grid method is used to simulate several types of maneuvers of KVLCC1 ship model. Stopping maneuvers with reversing propeller, turning rudder with/without propeller are simulated to predict the ship stopping performance. Turning circle maneuver is also simulated to predict the advance and comparisons with stopping distance of other stopping maneuvers are discussed. Self-propulsion simulation is conducted firstly to validate the present CFD approach through comparisons with available experiments. Stopping maneuver simulations start from the steady state of self-propulsion, then different types of stopping maneuver is carried out by controlling the propeller and rudder. In addition, deep and shallow water conditions are both computed to illustrate the water depth effect on the stopping performance. The predicted trajectory and ship speed of different stopping maneuvers are presented and analyzed. Detail information of flow visualizations including pressure distribution and wake flow during stopping maneuver are discussed to explain the stopping behavior. It is concluded that the turning circle maneuver is the most preferable way to avoid the collision in open sea. However, if the ship needs to stop in port or waterways, then the reversing propeller (RP) is better due to the fact that it meets the relatively shorter lateral deviation.

Dynamic manoeuvres of KCS in waves using URANS computations with overset grids

This paper presents a CFD URANS approach to model self-propelled free running maneouvres for autonomous or remote-controlled surface vessels in calm water and Stokes waves. The object of study in this paper is a benchmark container ship KCS. A hierarchy of overset grids are utilised, allowing active rudder motions while the vessel is undertaking 6 DoF turning circle and zig-zag manoeuvres. Body force propeller model (BFM) is adopted to drive the vessel at a constant approaching speed corresponds to Fr=0.26. Verification and validation study is performed for estimating the numerical uncertainties within the computations. In calm water, the computed vessel trajectories and velocities are compared against experimental data from literature and mathematical model (MM) based simulation results. Differences between URANS and experimental data are around 10.0%. After introducing waves, the manoeuvring behaviour of the vessel changes due to the presence of wave frequency loads and drift loads. The wave frequency loads exert fluctuations on measurements such as velocity, yaw rate, vessel encounted loads and etc., while the drift loads result in shift in the vessel’s trajectory especially for the turning circle manoeuvre.

Investigating the effect of rudder profile on 6DOF ship turning performance

Maneuverability is an important aspect of marine vehicle design. The performance of a rudder, as the most important means of maneuvering, has significant impacts on ship controllability characteristics. This study investigated the effect of five rudder profiles (NACA 0012, NACA0025, IFS, Fish tail, HSVA) on the turning characteristics of KCS containership model. This investigation was performed by direct simulation of the ship turning circle maneuver in computational fluid dynamic environment based on the ITTC verification procedure. All rudders were defined with the same lateral area. Simulations were conducted with the commercial software STAR-CCM+. The rudder turning and the ship's dynamic motion were modeled by the use of an overset technique and six-DOF dynamic solver, respectively. Roll, pitch and heave motions and forward speed reduction during the turning maneuver with different rudders were computed and compared. Results show that the rudder profiles designed specifically for marine applications (Fishtail, IFS and HSVA) perform better than the traditional NACA series.