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Hekkenberg R.g. - One of the best experts on this subject based on the ideXlab platform.
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Mesh properties for rans simulations of airfoil-shaped profiles: A case study of Rudder hydrodynamics
'MDPI AG', 2021Co-Authors: Lu Suli, Liu Jialun, Hekkenberg R.g.Abstract:A good mesh is a prerequisite for achieving reliable results from Computational Fluid Dynamics (CFD) calculations. Mesh properties include mesh types, computational domain sizes, and node distributions. However, in literature, we found no clear consensus about what these properties should be. In this article, we performed a case study on ship Rudders to determine what the suitable mesh properties are for airfoil-shaped profiles. A classic NACA 0012 profile is chosen as an example, and commercial packages ANSYS ICEM are applied for meshing with an ANSYS Fluent solver. With a strategy in consideration of relationships among different mesh properties, a comprehensive parametric investigation is conducted to study the impacts of these properties on the accuracy of Rudder hydrodynamic coefficients obtained by CFD methods. The step-by-step study outputs recommended Reynolds numbers, domain sizes, and near-and far-field node distributions for mesh types with distinct topology structures, i.e., C-mesh, O-mesh, H-mesh, and Hybrid-mesh. Specifically, the study shows that a critical Reynolds number is needed for the perspective of efficiency, while a domain extending 60 times of the chord length enables the boundary effects to be negligible. As for node distributions, the near-field nodes should be treated carefully, compared with those in the far-field. After that, corresponding mesh properties for different calculation objectives are illustrated in detail based on the characteristics of mesh types mentioned above. With the proposed strategy for mesh refinements, impacts of different mesh properties on Rudder hydrodynamics are clarified and recommended settings are applicable for other airfoil-shaped profiles such as wind turbines and marine propellers.Ship Design, Production and Operation
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Sixty years of research on ship Rudders: Effects of design choices on Rudder performance
'Informa UK Limited', 2017Co-Authors: Liu J., Hekkenberg R.g.Abstract:Rudders are primary steering devices for merchant ships. The main purpose of using Rudders is to generate forces for course keeping and manoeuvring. In exceptional cases, Rudders are also used for emergency stopping and roll stabilisation. Furthermore, Rudders affect propeller thrust efficiency and total ship resistance. Therefore, Rudders are important to navigation safety and transport efficiency. The performance of Rudders depends on the Rudder hydrodynamic characteristics, which are affected by the design choices. Scholarly articles concerning the design of Rudders date back more than 60 years. Moreover, a lot of knowledge fragments of Rudders exist in literature where ship manoeuvrability and fuel consumption are discussed. It is worthwhile to gather this information not only for researchers to advance the state-of-the-art development but also for designers to make proper choices. To have a contemporary vision of the Rudders, this paper presents a consolidated review of design impacts on Rudder performance in ship manoeuvrability, fuel consumption, and cavitation. The discussed design choices are Rudder working conditions (Reynolds numbers and angles of attack), profiles (sectional shapes), properties (area, thickness, span, chord, and Rudder aspect ratios), types (the position of the stock and the structural Rudder–hull connection), and interactions (among the hull, the propeller, and the Rudder). Further research is suggested on high-lift Rudder profiles, multiple-Rudder configurations and interactions among the hull, the propeller, and the Rudder. Recommendations for industry practices in the selection of the Rudder design choices are also given.Accepted Author ManuscriptShip Design, Production and Operation
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Interaction effects on hydrodynamic characteristics of twin Rudders
Harbin Engineering University, 2016Co-Authors: Liu J., Hekkenberg R.g.Abstract:In order to reach the required manoeuvrability, inland vessels often use twin Rudders, but the interaction effects are poorly understood. To achieve a proper configuration, this paper applies 2D RANS simulations to analyse the interaction effects on the twin-Rudder hydrodynamics. Various twin-Rudder configurations with different profiles and spacing of the Rudders are studied. RANS simulations are carried out with a k-w SST turbulence model and a pressure-based coupled algorithm. Commercial CFD package ANSYS Meshing and ANYSYS Fluent are applied as the mesh generator and the numerical solver. Series of NACA, IFS, and Wedge-tail profiles are tested and compared in various configurations. Finally, the interaction effects on twin-Rudder hydrodynamic characteristics are summarised.Ship Design, Production and Operation
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3D RANS simulations of shallow water effects on Rudder hydrodynamic characteristics
Harbin Engineering University, 2016Co-Authors: Liu J., Hekkenberg R.g.Abstract:An accurate estimation of the Rudder forces and moments is essential for manoeuvrability prediction. Previous research has shown that ships have different manoeuvring performance in deep and shallow water. Before considering the Rudder’s contribution to shallow water manoeuvring, it is meaningful to analyse the shallow water effects on the Rudder itself. In shallow water, the Rudder gets close to the channel bottom. Therefore, mirror effects are expected, which may greatly affect the Rudder effective aspect ratio and the generated Rudder forces. Instead of high-cost model tests and time consuming full ship CFD simulations, this paper applies 3D RANS methods to analyse the shallow water effects on Rudder hydrodynamic characteristics. 3D RANS simulations are carried out with a pressure-based coupled algorithm through ANSYS Fluent 16.2. The turbulence is simulated by a realisable k-e turbulence model. Based on a NACA 0020 profile, the method is validated through a comparison of the CFD results with the wind tunnel tests. Then, NACA 0020 spade Rudders with geometric aspect ratios of 1.2 and 1.5 are tested with different tip clearance. Rudder lift and drag coefficients are generated to calculate the normal force coefficient for manoeuvring simulations. Finally, shallow water effects on Rudder hydrodynamics are summarised
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Hydrodynamic Characteristics of Twin-Rudders at Small Attack Angles
2015Co-Authors: Liu J., Hekkenberg R.g.Abstract:RANS simulations are implemented to analyse the hydrodynamic characteristics of twin-Rudders, i.e. Flat plate Rudders, NACA Rudders, and Wedge-tail Rudders. The study mainly focuses on small attack angles. Results show that the NACA series is the most efficient profile while the Wedge-tail Rudder has the highest Rudder effectiveness.Marine and Transport TechnologyMechanical, Maritime and Materials Engineerin
Robert Hekkenberg - One of the best experts on this subject based on the ideXlab platform.
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Sixty years of research on ship Rudders: effects of design choices on Rudder performance
Ships and Offshore Structures, 2016Co-Authors: Robert HekkenbergAbstract:Rudders are primary steering devices for merchant ships. The main purpose of using Rudders is to generate forces for course keeping and manoeuvring. In exceptional cases, Rudders are also used for emergency stopping and roll stabilisation. Furthermore, Rudders affect propeller thrust efficiency and total ship resistance. Therefore, Rudders are important to navigation safety and transport efficiency. The performance of Rudders depends on the Rudder hydrodynamic characteristics, which are affected by the design choices. Scholarly articles concerning the design of Rudders date back more than 60 years. Moreover, a lot of knowledge fragments of Rudders exist in literature where ship manoeuvrability and fuel consumption are discussed. It is worthwhile to gather this information not only for researchers to advance the state-of-the-art development but also for designers to make proper choices. To have a contemporary vision of the Rudders, this paper presents a consolidated review of design impacts on Rudder performance in ship manoeuvrability, fuel consumption, and cavitation. The discussed design choices are Rudder working conditions (Reynolds numbers and angles of attack), profiles (sectional shapes), properties (area, thickness, span, chord, and Rudder aspect ratios), types (the position of the stock and the structural Rudder–hull connection), and interactions (among the hull, the propeller, and the Rudder). Further research is suggested on high-lift Rudder profiles, multiple-Rudder configurations and interactions among the hull, the propeller, and the Rudder. Recommendations for industry practices in the selection of the Rudder design choices are also given.
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interaction effects on hydrodynamic characteristics of twin Rudders
Proceedings 2016 International Conference on Maritime Technology, 2016Co-Authors: Robert HekkenbergAbstract:In order to reach the required manoeuvrability, inland vessels often use twin Rudders, but the interaction effects are poorly understood. To achieve a proper configuration, this paper applies 2D RANS simulations to analyse the interaction effects on the twin-Rudder hydrodynamics. Various twin-Rudder configurations with different profiles and spacing of the Rudders are studied. RANS simulations are carried out with a k-w SST turbulence model and a pressure-based coupled algorithm. Commercial CFD package ANSYS Meshing and ANYSYS Fluent are applied as the mesh generator and the numerical solver. Series of NACA, IFS, and Wedge-tail profiles are tested and compared in various configurations. Finally, the interaction effects on twin-Rudder hydrodynamic characteristics are summarised.
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hydrodynamic characteristics of twin Rudders at small attack angles
IMDC 2015: Proceedings of the 12th International Marine Design Conference Tokyo Japan 11-14 May 2015, 2015Co-Authors: Robert HekkenbergAbstract:RANS simulations are implemented to analyse the hydrodynamic characteristics of twin-Rudders, i.e. Flat plate Rudders, NACA Rudders, and Wedge-tail Rudders. The study mainly focuses on small attack angles. Results show that the NACA series is the most efficient profile while the Wedge-tail Rudder has the highest Rudder effectiveness.
Liu J. - One of the best experts on this subject based on the ideXlab platform.
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Sixty years of research on ship Rudders: Effects of design choices on Rudder performance
'Informa UK Limited', 2017Co-Authors: Liu J., Hekkenberg R.g.Abstract:Rudders are primary steering devices for merchant ships. The main purpose of using Rudders is to generate forces for course keeping and manoeuvring. In exceptional cases, Rudders are also used for emergency stopping and roll stabilisation. Furthermore, Rudders affect propeller thrust efficiency and total ship resistance. Therefore, Rudders are important to navigation safety and transport efficiency. The performance of Rudders depends on the Rudder hydrodynamic characteristics, which are affected by the design choices. Scholarly articles concerning the design of Rudders date back more than 60 years. Moreover, a lot of knowledge fragments of Rudders exist in literature where ship manoeuvrability and fuel consumption are discussed. It is worthwhile to gather this information not only for researchers to advance the state-of-the-art development but also for designers to make proper choices. To have a contemporary vision of the Rudders, this paper presents a consolidated review of design impacts on Rudder performance in ship manoeuvrability, fuel consumption, and cavitation. The discussed design choices are Rudder working conditions (Reynolds numbers and angles of attack), profiles (sectional shapes), properties (area, thickness, span, chord, and Rudder aspect ratios), types (the position of the stock and the structural Rudder–hull connection), and interactions (among the hull, the propeller, and the Rudder). Further research is suggested on high-lift Rudder profiles, multiple-Rudder configurations and interactions among the hull, the propeller, and the Rudder. Recommendations for industry practices in the selection of the Rudder design choices are also given.Accepted Author ManuscriptShip Design, Production and Operation
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Interaction effects on hydrodynamic characteristics of twin Rudders
Harbin Engineering University, 2016Co-Authors: Liu J., Hekkenberg R.g.Abstract:In order to reach the required manoeuvrability, inland vessels often use twin Rudders, but the interaction effects are poorly understood. To achieve a proper configuration, this paper applies 2D RANS simulations to analyse the interaction effects on the twin-Rudder hydrodynamics. Various twin-Rudder configurations with different profiles and spacing of the Rudders are studied. RANS simulations are carried out with a k-w SST turbulence model and a pressure-based coupled algorithm. Commercial CFD package ANSYS Meshing and ANYSYS Fluent are applied as the mesh generator and the numerical solver. Series of NACA, IFS, and Wedge-tail profiles are tested and compared in various configurations. Finally, the interaction effects on twin-Rudder hydrodynamic characteristics are summarised.Ship Design, Production and Operation
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3D RANS simulations of shallow water effects on Rudder hydrodynamic characteristics
Harbin Engineering University, 2016Co-Authors: Liu J., Hekkenberg R.g.Abstract:An accurate estimation of the Rudder forces and moments is essential for manoeuvrability prediction. Previous research has shown that ships have different manoeuvring performance in deep and shallow water. Before considering the Rudder’s contribution to shallow water manoeuvring, it is meaningful to analyse the shallow water effects on the Rudder itself. In shallow water, the Rudder gets close to the channel bottom. Therefore, mirror effects are expected, which may greatly affect the Rudder effective aspect ratio and the generated Rudder forces. Instead of high-cost model tests and time consuming full ship CFD simulations, this paper applies 3D RANS methods to analyse the shallow water effects on Rudder hydrodynamic characteristics. 3D RANS simulations are carried out with a pressure-based coupled algorithm through ANSYS Fluent 16.2. The turbulence is simulated by a realisable k-e turbulence model. Based on a NACA 0020 profile, the method is validated through a comparison of the CFD results with the wind tunnel tests. Then, NACA 0020 spade Rudders with geometric aspect ratios of 1.2 and 1.5 are tested with different tip clearance. Rudder lift and drag coefficients are generated to calculate the normal force coefficient for manoeuvring simulations. Finally, shallow water effects on Rudder hydrodynamics are summarised
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Hydrodynamic Characteristics of Twin-Rudders at Small Attack Angles
2015Co-Authors: Liu J., Hekkenberg R.g.Abstract:RANS simulations are implemented to analyse the hydrodynamic characteristics of twin-Rudders, i.e. Flat plate Rudders, NACA Rudders, and Wedge-tail Rudders. The study mainly focuses on small attack angles. Results show that the NACA series is the most efficient profile while the Wedge-tail Rudder has the highest Rudder effectiveness.Marine and Transport TechnologyMechanical, Maritime and Materials Engineerin
Christoph Michael Steinbach - One of the best experts on this subject based on the ideXlab platform.
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application of energy saving fins on Rudders
ASME 2015 34th International Conference on Ocean Offshore and Arctic Engineering, 2015Co-Authors: Arne Falkenhorst, Stefan Kruger, Christoph Michael SteinbachAbstract:Due to rising fuel oil prices in the last decade as well as rising design speeds, it has become common practice to build Rudders with twisted leading edges to minimize resistance and cavitation risk. The next step in this development is the application of fins on to the Rudder. The aim is to generate a distinct amount of thrust through the fins by retrieving rotational kinetic energy from the propeller slipstream. This paper presents a fast method to design and calculate Rudder fins in the propeller slipstream, which has been implemented in the ship design environment E4.Because of his working principle, the propeller induces velocities to its slipstream. In the usual setup, the Rudder is placed behind the propeller to generate higher steering forces caused by the higher inflow speed in the slipstream. In this arrangement, propeller and Rudder together are forming a rotor–stator system. The gains of the stator can be maximized by adding fins to the Rudder. The main challenge of a fin design is the maximization and prediction of the regained thrust from the propeller slipstream. In order to do this, a steady, three dimensional, direct panel method is used to calculate the flow around the Rudder and fin bodies, from which later the pressures and forces are evaluated. A lifting line method is used to predict the inflow velocities caused by the vortex dominated propeller slipstream on each panel. A special focus is on the treatment of the vortex wake, as crossing wake elements can lead to numerical instabilities and a wrong wake alignment produces bad thrust predictions.For the purpose of Rudder design steady computation should be preferred over fully unsteady computation, since only time average integral values are of interest and the degrees of freedom are reduced to the relevant ones. For example, it is not necessary to know the fluctuation of the angle of attack for the basic design of the profile respective the leading edge of the foil, only the mean value is needed.In the industrial practice, Rudder fins are not often used because the calculation is difficult. Until now it is more expensive to design and build the fins than the savings earned by the ship owner. This phenomenon will change in the next years due to better calculations and rising fuel oil prices.Copyright © 2015 by ASME
Masataka Fujino - One of the best experts on this subject based on the ideXlab platform.
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assessment of a mathematical model for the manoeuvring motion of a twin propeller twin Rudder ship
International shipbuilding progress, 2003Co-Authors: Seung Keon Lee, Masataka FujinoAbstract:The MMG mathematical model [1] is well known and widely used for describing the manoeuvring motion of a ship. The MMG model is a modular type mathematical model which has proven to be useful in predicting various aspects of manoeuvring motion. However, this model was originally developed for the single-propeller single-Rudder ship. Nowadays there are many multi-propeller multi-Rudder ships, but little is known about the manoeuvring characteristics of the multi-propeller multi-Rudder ship. In this paper, the authors develop the mathematical model to predict the manoeuvring motion of a twin-propeller twin-Rudder ship, which was selected as one of the most popular configurations of multi-propeller multi-Rudder ships. Initially, the various parameters included in the mathematical model for manoeuvring motion are investigated experimentally for a twin-propeller twin-Rudder ship. The authors subsequently modified the mathematical model of the single-propeller single-Rudder ship, and proposed a new mathematical model for the twin-propeller twin-Rudder ship [2]. Finally, the predicted manoeuvring motion of the twin-propeller twin-Rudder ship was compared with the test results of a free-sailing model in order to examine the validity of the proposed mathematical model.
