The influence of sway-roll coupling on the dynamics of an inverted sailing yacht in waves. The ability of a sailing yacht to re-right in waves after capsize will influence the safety of those on board in extreme conditions.
The aim of this project is to incorporate the effects of sway-roll coupling into a numerical simulation of the behaviour of an inverted yacht in waves to assess design features which influence re-righting. Experimental work being conducted during 2001 will be extended to ....The influence of sway-roll coupling on the dynamics of an inverted sailing yacht in waves. The ability of a sailing yacht to re-right in waves after capsize will influence the safety of those on board in extreme conditions.
The aim of this project is to incorporate the effects of sway-roll coupling into a numerical simulation of the behaviour of an inverted yacht in waves to assess design features which influence re-righting. Experimental work being conducted during 2001 will be extended to enable the forces on a model of an inverted yacht in a breaking wave to be determined. and incorporated along with theoretical predictions into the simulation.Read moreRead less
Hydroelasticity of compliant offshore structures. Australia's rich offshore oil and gas reserves are awaiting extensive deepwater extraction. However, there is still a lack of in-depth knowledge in the dynamic behavior of deepwater structures to ensure safe and cost-effective production. We hereby propose hydroelasticity theories and modelling techniques to investigate dynamic fluid-structure interaction problems for compliant offshore structures. We also propose innovative experiments to verify ....Hydroelasticity of compliant offshore structures. Australia's rich offshore oil and gas reserves are awaiting extensive deepwater extraction. However, there is still a lack of in-depth knowledge in the dynamic behavior of deepwater structures to ensure safe and cost-effective production. We hereby propose hydroelasticity theories and modelling techniques to investigate dynamic fluid-structure interaction problems for compliant offshore structures. We also propose innovative experiments to verify the theoretical work. One application is to configure a freestanding compliant tower to suit prospective deepwater oil and gas fields off North-West Australia. Expected outcomes include theoretical and experimental advances in deepwater offshore mechanics and practical computation tools for industry applications.Read moreRead less
Environmental Study of the Wavemaking Characteristics of High-Speed Ferries. The aim is to perform a study of the wave-making characteristics of high-speed ferries of the monohull, catamaran, and multihull type in order to be able to predict their environmental impact on river banks and sea shores. The significance is that a number of ferry services have been curtailed or cancelled as a result of suspected wave damage. The outcome will be a methodology for computing the wave system produced by s ....Environmental Study of the Wavemaking Characteristics of High-Speed Ferries. The aim is to perform a study of the wave-making characteristics of high-speed ferries of the monohull, catamaran, and multihull type in order to be able to predict their environmental impact on river banks and sea shores. The significance is that a number of ferry services have been curtailed or cancelled as a result of suspected wave damage. The outcome will be a methodology for computing the wave system produced by such ferries in water of any depth. The nature of the rate of decay of the wave system will be included in the analysis.Read moreRead less
Optimal nose shaping for delayed boundary-layer separation and transition in axisymmetric flow. The aim of this project is to design a smooth nose for a body of revolution placed in axisymmetric flow of a viscous fluid at high Reynolds number, such that the boundary layer on the body remains unseparated. This can always be done with a sufficiently long nose, but our objective here is to minimise the necessary nose length. Outer potential flows will be provided via ring sources. The potential flo ....Optimal nose shaping for delayed boundary-layer separation and transition in axisymmetric flow. The aim of this project is to design a smooth nose for a body of revolution placed in axisymmetric flow of a viscous fluid at high Reynolds number, such that the boundary layer on the body remains unseparated. This can always be done with a sufficiently long nose, but our objective here is to minimise the necessary nose length. Outer potential flows will be provided via ring sources. The potential flows will be used to determine inner boundary layer solutions. Transition-to-turbulence will be considered by undertaking 2D and 3D stability computations.Read moreRead less
MODAL AND DIRECTIONAL CHARACTERISTICS OF SEASTATES AND THEIR IMPACT ON DYNAMICS OF MOORED OFFSHORE SYSTEMS. Under certain conditions a typical sea can becomes bimodal comprising of wind-driven seas and long period swells interacting from two directions. Using a nonlinear model, the occurrence and characteristics of bimodal and bi-directional seastates are quantified.
Low frequency oscillations of a moored offshore structure have profound design influence on the mooring system. A nonlinear res ....MODAL AND DIRECTIONAL CHARACTERISTICS OF SEASTATES AND THEIR IMPACT ON DYNAMICS OF MOORED OFFSHORE SYSTEMS. Under certain conditions a typical sea can becomes bimodal comprising of wind-driven seas and long period swells interacting from two directions. Using a nonlinear model, the occurrence and characteristics of bimodal and bi-directional seastates are quantified.
Low frequency oscillations of a moored offshore structure have profound design influence on the mooring system. A nonlinear response model for a floating vessel in bimodal and bi-directional seastates, will be developed using nonlinear dynamics techniques. The numerical models for the environment and the floating platform will be validated by experiments at the Ocean Basin in Canada.
The project adopts a holistic approach by considering the environment and the moored platform as a complex natural system. With excellent opportunities for technology transfer, the project also benefits from substantial in-kind contributions of the overseas PIs.
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A hybrid approach to predict the structure-borne noise transmission in ship structures using a waveguide method and Statistical Energy Analysis. The prediction of structure-borne noise transmission in large welded ship structures is required, in order to design maritime vessels with greater ship power and reduced weight, without increasing the noise levels. The aim of this project is to develop a hybrid approach for structural dynamic analyses using an analytical waveguide method and Statistical ....A hybrid approach to predict the structure-borne noise transmission in ship structures using a waveguide method and Statistical Energy Analysis. The prediction of structure-borne noise transmission in large welded ship structures is required, in order to design maritime vessels with greater ship power and reduced weight, without increasing the noise levels. The aim of this project is to develop a hybrid approach for structural dynamic analyses using an analytical waveguide method and Statistical Energy Analysis. The theoretical estimation and associated experimental measurement of the SEA parameters (modal density, coupling and internal loss factors) form the basis for the hybrid approach. The outcomes will result in improved predictive techniques for dynamic analyses of large complex resonant structures.Read moreRead less
Dominant flow noise source identification for ducted marine propellers. Ducted marine propellers are becoming an increasing alternative to conventional open propellers. Understanding flow-induced noise generated by ducted propellers is a key consideration in the design process to minimise noise emission. This project aims to develop new methods to identify turbulent flow sources of a ducted marine propeller that dominate sound. High-fidelity numerical methods will be developed to study the compl ....Dominant flow noise source identification for ducted marine propellers. Ducted marine propellers are becoming an increasing alternative to conventional open propellers. Understanding flow-induced noise generated by ducted propellers is a key consideration in the design process to minimise noise emission. This project aims to develop new methods to identify turbulent flow sources of a ducted marine propeller that dominate sound. High-fidelity numerical methods will be developed to study the complex interaction between inflow turbulence, support struts, propeller blades and duct structure. Successful identification of the dominant sources of noise will allow for targeted noise mitigation strategies with significant impact for stealth of military vessels and reduction of underwater noise pollution on marine life.Read moreRead less
Prediction of radiated noise from marine propellers. Underwater noise radiated from marine vessels is a significant problem for research, fishing and military vessels, and is a major source of pollution in the marine environment. The major source contributing to underwater noise is due to the propeller. This work will develop numerical models with experimental validation that can accurately predict the sources of noise generated by marine propellers and acoustic signatures of marine vessels due ....Prediction of radiated noise from marine propellers. Underwater noise radiated from marine vessels is a significant problem for research, fishing and military vessels, and is a major source of pollution in the marine environment. The major source contributing to underwater noise is due to the propeller. This work will develop numerical models with experimental validation that can accurately predict the sources of noise generated by marine propellers and acoustic signatures of marine vessels due to propeller motion. This work has great significance for Australia’s construction and military maritime industries. The technologies developed in this project are also applicable to rotors in other industries such as in aircraft, helicopters and wind turbines.Read moreRead less
Mathematical and computational analysis of ship wakes. This project aims to develop mathematical and computational tools to compute the energy in a given ship wake and to determine a range of properties of a ship by taking simple measurements of the water height as the ship travels past. The expected outcomes of this project include a suite of algorithms that back-calculate the hull shape and operating conditions of a moving ship given only the surface height data measured at a single point. The ....Mathematical and computational analysis of ship wakes. This project aims to develop mathematical and computational tools to compute the energy in a given ship wake and to determine a range of properties of a ship by taking simple measurements of the water height as the ship travels past. The expected outcomes of this project include a suite of algorithms that back-calculate the hull shape and operating conditions of a moving ship given only the surface height data measured at a single point. These results should have direct implications for measuring damage to coastal zones by ship wakes and for surveillance of shipping channels.Read moreRead less
Development of Models for the Three-Dimensional Analysis of Jack-Up Structures. Mobile jack-up structures perform most of the world's offshore drilling in water depths up to 120m, but have a higher accident rate then fixed installations. To improve their safety, this research will develop the framework for the integrated assessment of jack-up behaviour in three dimensions. To achieve this, an advanced plasticity model that describes cyclic behaviour of the circular shallow foundations of jack-up ....Development of Models for the Three-Dimensional Analysis of Jack-Up Structures. Mobile jack-up structures perform most of the world's offshore drilling in water depths up to 120m, but have a higher accident rate then fixed installations. To improve their safety, this research will develop the framework for the integrated assessment of jack-up behaviour in three dimensions. To achieve this, an advanced plasticity model that describes cyclic behaviour of the circular shallow foundations of jack-ups in both clay and sand will be developed and incorporated with random wave loading of seas in a dynamic structural analysis program. The anticipated advantages of the modelling techniques will be assessed against existing two dimensional industry guidelines and monitored field data. Read moreRead less