Flow-induced oscillation in flexible tubes: experimental and numerical investigation of mechanism and onset. We seek to understand when instability arises in flow over very deformable structures. This will help us to design highly flexible structures specifically either to avoid the danger of flow-induced oscillations, which may be damaging (cardiac surgery, sails, parachutes), or in other circumstances to take advantage of them as an innovative way involving no sliding-parts mechanisms to crea ....Flow-induced oscillation in flexible tubes: experimental and numerical investigation of mechanism and onset. We seek to understand when instability arises in flow over very deformable structures. This will help us to design highly flexible structures specifically either to avoid the danger of flow-induced oscillations, which may be damaging (cardiac surgery, sails, parachutes), or in other circumstances to take advantage of them as an innovative way involving no sliding-parts mechanisms to create vibration, or flow pulsation, or sound, or motion (as in swimming-pool cleaners). Confidence in designing with highly flexible tubes will allow minimal resource consumption in manufacture of products to transport fluids, and will allow design use of the flow limitation property, whereby such a tube can control flow-rate.Read moreRead less
Modelling and Measurement of Flow-Structure Dynamics in the Human Upper Airway. Sleep disruption due to the common and disabling conditions of snoring and obstruction of the human upper airway can result in chronic fatigue, lost work and accidents caused by daytime drowsiness. To date the behaviour of the upper airway has not been adequately studied in terms able to reveal the mechanical causes of these conditions. This deficiency is addressed through the development and use of simulation tools ....Modelling and Measurement of Flow-Structure Dynamics in the Human Upper Airway. Sleep disruption due to the common and disabling conditions of snoring and obstruction of the human upper airway can result in chronic fatigue, lost work and accidents caused by daytime drowsiness. To date the behaviour of the upper airway has not been adequately studied in terms able to reveal the mechanical causes of these conditions. This deficiency is addressed through the development and use of simulation tools and measurement techniques that will elucidate the flow-structure dynamics leading to new diagnostic and improved treatment methods. Simulating the effect of treatment on any individual will permit it to be chosen to maximise its efficacy for a problem that costs the nation an estimated $2 Billion per year in lost productivity.Read moreRead less
Fluctuations in the properties of nonequilibrium fluids and the influence of thermostatting mechanisms. The behaviour of nonequilibrium fluids will be studied by combining ideas from liquid state theory, statistical mechanics and dynamical systems theory. This work will result in development and testing of mathematical expressions (Fluctuation Theorems) that are consistent with the Second Law of Thermodynamics, which determines the direction of any change in any macroscopic system, but are also ....Fluctuations in the properties of nonequilibrium fluids and the influence of thermostatting mechanisms. The behaviour of nonequilibrium fluids will be studied by combining ideas from liquid state theory, statistical mechanics and dynamical systems theory. This work will result in development and testing of mathematical expressions (Fluctuation Theorems) that are consistent with the Second Law of Thermodynamics, which determines the direction of any change in any macroscopic system, but are also applicable to microscopic systems. The expressions will determine the probability that finite sized systems will violate the Second Law for small periods of time and will therefore contribute to development of a fundamental understanding of microscopic systems and the development of nanotechnology.
Read moreRead less
Fluid properties and chaotic dynamics in equilibrium and nonequilibrium states. Over the last decade a revolution has been taking place in nonequilibrium statistical mechanics [Physics Today, Sept, 2002]. This revolution is characterized by adapting the mathematical theory of chaos to nonequilibrium statistical mechanics. Fundamental new theorems and algorithms for computing transport coefficients have been derived. The CIs have played a key role in this revolution. We seek to broaden these dev ....Fluid properties and chaotic dynamics in equilibrium and nonequilibrium states. Over the last decade a revolution has been taking place in nonequilibrium statistical mechanics [Physics Today, Sept, 2002]. This revolution is characterized by adapting the mathematical theory of chaos to nonequilibrium statistical mechanics. Fundamental new theorems and algorithms for computing transport coefficients have been derived. The CIs have played a key role in this revolution. We seek to broaden these developments by: generalizing a theorem which relates transport coefficients to chaoticity; detailed studies of the influence of thermostatting mechanisms on nonequilibrium chaoticity and fluctuations, and by understanding the range of applicability of a nonequilibrium fluctuation theorem for non-isoenergetic systems.Read moreRead less
Unravelling the scale interactions of wall turbulence: experiment, physical modelling, next-generation numerical simulation. Turbulent fluid flows near solid surfaces are present in many areas of everyday life: from the drag experienced on air, sea and road vehicles, to governing the mixing processes in combustion chambers, and in the transport of pollutants and particulates in our cities and towns. Unfortunately our understanding of these complex flows is limited, and hence so to is our ability ....Unravelling the scale interactions of wall turbulence: experiment, physical modelling, next-generation numerical simulation. Turbulent fluid flows near solid surfaces are present in many areas of everyday life: from the drag experienced on air, sea and road vehicles, to governing the mixing processes in combustion chambers, and in the transport of pollutants and particulates in our cities and towns. Unfortunately our understanding of these complex flows is limited, and hence so to is our ability to model or control them. This project addresses this problem with the goal of providing new physical insights and models that can be used for efficient and accurate numerical simulations. The simulations will not only compute the average statistics but also the time-varying properties, which are crucial in many engineering and environmental processes.Read moreRead less
Stability, transition and heat transfer in thermally coupled natural convection boundary layers. Thermally coupled natural convection systems occur when a conducting vertical wall separates two fluids at different temperatures. Such configurations occur, for example, at a window separating the interior of a room from the outside or when a container of fluid is placed in a refrigerator. Improved building heating/cooling and ventilation, and more efficient refrigeration systems, require a thoroug ....Stability, transition and heat transfer in thermally coupled natural convection boundary layers. Thermally coupled natural convection systems occur when a conducting vertical wall separates two fluids at different temperatures. Such configurations occur, for example, at a window separating the interior of a room from the outside or when a container of fluid is placed in a refrigerator. Improved building heating/cooling and ventilation, and more efficient refrigeration systems, require a thorough understanding and predictive capability for these flows. This project will develop experimental, numerical and analytic tools to predict these flows and provide simple scaling relations for bulk flow parameters such as the heat transfer across the wall, which will be of immediate use in the associated industries.Read moreRead less
Practical wall-turbulence drag reduction through adaptive control. Long term increases in the price of aviation fuel disproportionately impacts on Australian carriers, given our geographic isolation and the resulting greater percentage of long-haul flights. The resulting higher fares will also have a direct impact on international tourism to Australia. One way to reduce the impact of rising fuel cost, and to reduce CO2 and other emissions at the same time, is to decrease drag on aircraft. This ....Practical wall-turbulence drag reduction through adaptive control. Long term increases in the price of aviation fuel disproportionately impacts on Australian carriers, given our geographic isolation and the resulting greater percentage of long-haul flights. The resulting higher fares will also have a direct impact on international tourism to Australia. One way to reduce the impact of rising fuel cost, and to reduce CO2 and other emissions at the same time, is to decrease drag on aircraft. This project will develop understanding in wall turbulence and adaptive control, and use this to experimentally demonstrate active reductions in skin friction drag. The results are equally applicable to a range of other applications including sea transport, pipe flows and combustor designs.Read moreRead less
Enhancement of Heat Transfer by Stimulated Transition to Turbulence in Natural Convection Boundary Layers on Heated Walls. The aim of this project is to increase the heat transfer from heated vertical surfaces to an ambient fluid by stimulating an early transition to turbulence. Such passive heat transfer occurs in heat transfer devices, natural ventilation systems and in many environmental settings. Enhanced heat transfer will greatly improve the performance of these systems. The project will ....Enhancement of Heat Transfer by Stimulated Transition to Turbulence in Natural Convection Boundary Layers on Heated Walls. The aim of this project is to increase the heat transfer from heated vertical surfaces to an ambient fluid by stimulating an early transition to turbulence. Such passive heat transfer occurs in heat transfer devices, natural ventilation systems and in many environmental settings. Enhanced heat transfer will greatly improve the performance of these systems. The project will provide the length scales, frequency and amplification rate for the occurence of the secondary spanwise mode that is the primary mechanism for turbulent transition. This will provide guidance for the development of appropriate roughness elements and heating length and time scales.Read moreRead less
Robust fluid mixing through topological chaos. The Australian chemicals and plastics industry has an annual turnover of over $20 billion and employs over 77,000 people; fluid mixing is fundamental to this industry, yet the industry is recognised as underinvesting in research and development in this essential area. Furthermore, frontier technologies such as biotechnology and the next generation of smart materials also crucially rely on fluid mixing. This project aims to evaluate a new paradigm ( ....Robust fluid mixing through topological chaos. The Australian chemicals and plastics industry has an annual turnover of over $20 billion and employs over 77,000 people; fluid mixing is fundamental to this industry, yet the industry is recognised as underinvesting in research and development in this essential area. Furthermore, frontier technologies such as biotechnology and the next generation of smart materials also crucially rely on fluid mixing. This project aims to evaluate a new paradigm (topological chaos) for the design of mixers, to provide better and more robust mixers that work from microscopic to industrial scales.Read moreRead less
Systematically model the large-scale complexity of turbulent floods and thin film flows. This project continues development of new models, and computer
simulation, of turbulent flood, river and estuarine flow. The models
will be based systematically upon established turbulence models to
resolve accurately the complex physical processes. The development of
new and robust computer models for thin layers of coating fluid will
aid many industrial processes. We also aim to provide correct ini ....Systematically model the large-scale complexity of turbulent floods and thin film flows. This project continues development of new models, and computer
simulation, of turbulent flood, river and estuarine flow. The models
will be based systematically upon established turbulence models to
resolve accurately the complex physical processes. The development of
new and robust computer models for thin layers of coating fluid will
aid many industrial processes. We also aim to provide correct initial
conditions and boundary conditions for simpler cases of the above
flows. The approach leads to a greater understanding of the range of
applicability of the models through better estimating the errors in the
modelling process. The project develops a fundamental enabling
methodology for engineering and the sciences.
Read moreRead less