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
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
Application of exact coherent structures to transition and turbulence. This project aims to understand coherent structures and devise methods to prevent bypass transition to turbulence and reduce turbulent wall drag. Coherent structures in turbulence may be identified with nonlinear solutions of the exact equations of motion. Such "exact" coherent structures have their Reynolds number dependence described explicitly and apply for moderate to very large Reynolds numbers, well above the range of f ....Application of exact coherent structures to transition and turbulence. This project aims to understand coherent structures and devise methods to prevent bypass transition to turbulence and reduce turbulent wall drag. Coherent structures in turbulence may be identified with nonlinear solutions of the exact equations of motion. Such "exact" coherent structures have their Reynolds number dependence described explicitly and apply for moderate to very large Reynolds numbers, well above the range of full Navier–Stokes calculations. Understanding the fundamentals of turbulence is expected to lead to more efficient and cheaper air transportation, and better tools for climate prediction and short-term weather forecasting.Read moreRead less
A Novel Approach To Flow Control By Topography. The project will resolve important questions concerning the influence of boundary topography on transition to turbulence and on the exact coherent structures forming the backbone of turbulence.
The canonical topography known from previous work by one of the investigators is a wavy wall and, as well as resolving important issues in flow physics, the research is relevant to many flows of importance such roughness induced transition on aircraft wings, ....A Novel Approach To Flow Control By Topography. The project will resolve important questions concerning the influence of boundary topography on transition to turbulence and on the exact coherent structures forming the backbone of turbulence.
The canonical topography known from previous work by one of the investigators is a wavy wall and, as well as resolving important issues in flow physics, the research is relevant to many flows of importance such roughness induced transition on aircraft wings, flows in heat transfer/mixing devices, blood flow and the influence of topography on the atmospheric boundary layer.
Expected outcomes are an understanding of the interplay between transitional and turbulent flows with wall topography together with strategies to enhance mixing and drag reduction.Read moreRead less
The effect of turbulence scale and intensity on water flow measurement using ultrasonic techniques. Management of water resources and water distribution networks is important as Australia and the world face increasing water shortages. A significant aspect of water management is prevention of supply losses in urban and non-urban water distribution networks - a vital factor in improving water security of Australian cities and agricultural production regions. This research will develop ultrasonic f ....The effect of turbulence scale and intensity on water flow measurement using ultrasonic techniques. Management of water resources and water distribution networks is important as Australia and the world face increasing water shortages. A significant aspect of water management is prevention of supply losses in urban and non-urban water distribution networks - a vital factor in improving water security of Australian cities and agricultural production regions. This research will develop ultrasonic flow-velocity technology, which can be retrofitted to existing water distribution networks, providing distributed high precision water flow measurement systems that can prevent the loss each year of more than 155GL of water through leaks and burst in Australia's capital cities alone.Read moreRead less
Enhancing passive cooling using flexible baffles. The project aims to develop a novel passive strategy using fluid-structure-thermal interactions to enhance passive cooling by natural convection and improve the energy efficiency of engineering systems. Comparing to the existing strategies, the new strategy does not require driving fan or pump and is quiet, reliable, self-adaptive and economical. The Multiphysics embodied in the proposal is at the leading edge of the field. Expected outcomes incl ....Enhancing passive cooling using flexible baffles. The project aims to develop a novel passive strategy using fluid-structure-thermal interactions to enhance passive cooling by natural convection and improve the energy efficiency of engineering systems. Comparing to the existing strategies, the new strategy does not require driving fan or pump and is quiet, reliable, self-adaptive and economical. The Multiphysics embodied in the proposal is at the leading edge of the field. Expected outcomes include advanced understanding of the complex Multiphysics and design rules for enhancing passive cooling by natural convection using flexible baffles. The research is expected to bring direct economic benefit to relevant industry and significant environmental and social benefit to the general public.Read moreRead less
Catastrophic transition to turbulence in rotation-dominated flows. Rotation-dominated flows are very common in engineering applications and fluid dynamics of the Earth's atmosphere, oceans, and core. Such flows are known to make a sudden transition from an orderly to an energetic turbulent state and this project aims to discover the reason why.
Optimum design of hydraulic structures in rural and urban Australia: dealing with floods and droughts. Australia's long-term forecast suggests the occurrence of longer and more frequent droughts, and more intense flood events. The project will study the fundamental hydrodynamic processes in hydraulic structures and aims to develop new innovative designs derived from process based approach for optimum operation in rural and urban Australia.
Quantification of heat release, NOx emissions and soot from high temperature gaseous flames. The ongoing importance of Australia's minerals processing sector depends on advanced combustion technology to minimise the emission of NOx and other greenhouse gases. The heat release and NOx emissions from the high temperature flames used in such processes is known to depend strongly on the presence of soot. However their optimisation and design is limited by a lack of fundamental data under relevant c ....Quantification of heat release, NOx emissions and soot from high temperature gaseous flames. The ongoing importance of Australia's minerals processing sector depends on advanced combustion technology to minimise the emission of NOx and other greenhouse gases. The heat release and NOx emissions from the high temperature flames used in such processes is known to depend strongly on the presence of soot. However their optimisation and design is limited by a lack of fundamental data under relevant conditions. To address this need, new measurements and analysis will be performed to quantify the complex relationship between turbulent mixing, soot formation, heat release and NOx emissions under high temperature conditions of both fundamental and practical significance.
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Geometry of wall-turbulence and its potential to advance scalable models. This project aims to unravel the connections between the statistical geometry of wall-turbulence and the dynamical interactions of its instantaneous motions. Predicting the complex behaviour of turbulent fluid flow over surfaces in relative motion is central to atmospheric modelling for climate and agriculture, and reducing the environmental effect of fossil fuel usage. Wall-turbulence statistics organise according to a pr ....Geometry of wall-turbulence and its potential to advance scalable models. This project aims to unravel the connections between the statistical geometry of wall-turbulence and the dynamical interactions of its instantaneous motions. Predicting the complex behaviour of turbulent fluid flow over surfaces in relative motion is central to atmospheric modelling for climate and agriculture, and reducing the environmental effect of fossil fuel usage. Wall-turbulence statistics organise according to a predictable geometric structure, and the notorious complexity of turbulent wall-flow dynamics could be clarified through its inherent geometry. This project expects to construct a basis for predicting engineering and atmospheric wall-flows, which would enhance atmospheric flow prediction, reduce energy consumption and further environmental sustainability.Read moreRead less