Transition of thermal boundary layers on heated flat and curved surfaces. This project aims to study the laminar to turbulent transition of the thermal boundary layer (TBL). The state of the TBL determines the heat transfer rate and energy efficiency of natural convection heat exchangers and heat dissipation systems. The intended outcome is to understand the TBL’s transitional behaviour and develop effective strategies for stimulating TBL transition to enhance heat transfer. This project will de ....Transition of thermal boundary layers on heated flat and curved surfaces. This project aims to study the laminar to turbulent transition of the thermal boundary layer (TBL). The state of the TBL determines the heat transfer rate and energy efficiency of natural convection heat exchangers and heat dissipation systems. The intended outcome is to understand the TBL’s transitional behaviour and develop effective strategies for stimulating TBL transition to enhance heat transfer. This project will develop a high-resolution, low-cost and easy-to-implement three-dimensional volumetric flow measurement technique based on stereoscopic shadowgraph and use it to study the TBL transition. This technique should provide a powerful tool for fluid mechanics and heat transfer research.Read moreRead less
Turbulent mixing of a passive scalar. Turbulence is the usual state of fluid motion. This proposal will increase Australia's expertise in fundamental turbulence research, especially in the area of turbulent mixing, which is of major importance in many natural and engineering problems involving combustion, chemical reactions and pollution. A better knowledge of mixing at small scales will lead to more efficient combustion, savings in energy expenditure as well as a reduction in pollutant emiss ....Turbulent mixing of a passive scalar. Turbulence is the usual state of fluid motion. This proposal will increase Australia's expertise in fundamental turbulence research, especially in the area of turbulent mixing, which is of major importance in many natural and engineering problems involving combustion, chemical reactions and pollution. A better knowledge of mixing at small scales will lead to more efficient combustion, savings in energy expenditure as well as a reduction in pollutant emissions. Read moreRead less
Entrainment and Mixing in Turbulent Negatively Buoyant Jets and Fountains. The project intends to develop tools to accurate predict fountain flows. Volcanic eruptions, building ventilation and brine discharge from desalination plants are all examples of turbulent fountains and negatively buoyant jets. The project aims to conduct an investigation into the turbulent structure of fountains and negatively buoyant jets using numerical simulation and laboratory experiments, and to assess the accuracy ....Entrainment and Mixing in Turbulent Negatively Buoyant Jets and Fountains. The project intends to develop tools to accurate predict fountain flows. Volcanic eruptions, building ventilation and brine discharge from desalination plants are all examples of turbulent fountains and negatively buoyant jets. The project aims to conduct an investigation into the turbulent structure of fountains and negatively buoyant jets using numerical simulation and laboratory experiments, and to assess the accuracy of the commonly used integral models and test the effect of the use of more accurate entrainment relations. This may have a range of applications – enabling better prediction of environmental impacts, reduction of the adverse effects of the discharge of pollutants, and reduction in energy consumption in building ventilation and other industrial applications.Read moreRead less
Thermal stratification, overturning and mixing in riverine environments. Thermal stratification is common in Australia's rivers due to our hot, drought-prone climate and high human demands relative to available supply, which has led to a significant reduction in flows relative to natural levels. Thermal stratification inhibits mixing, creating stagnant conditions characterised by low oxygen levels and increased concentrations of contaminants, leading to algal blooms, fish kills and systemic dama ....Thermal stratification, overturning and mixing in riverine environments. Thermal stratification is common in Australia's rivers due to our hot, drought-prone climate and high human demands relative to available supply, which has led to a significant reduction in flows relative to natural levels. Thermal stratification inhibits mixing, creating stagnant conditions characterised by low oxygen levels and increased concentrations of contaminants, leading to algal blooms, fish kills and systemic damage to ecosystems. The aim of this project is to develop predictive models for the effects of physical processes such as night-time cooling, wind, turbulence and currents on riverine thermal stratification. This is expected to enable a more accurate determination of the flow rates required to maintain the health of our river systems.Read moreRead less
Force Interactions in Packed and Fluidised Beds at Micro-Scale Operation. Industrial processing in the 20th century was about increasing size to gain benefit from economies of scale. This century, the focus is on micro devices like lab-on-a-chip and high speed computer processors that deliver their product directly to the consumer. There are significant obstacles facing this new technology. Mixing is reduced due to laminar flow, and a large amount of energy is needed to move the fluid through su ....Force Interactions in Packed and Fluidised Beds at Micro-Scale Operation. Industrial processing in the 20th century was about increasing size to gain benefit from economies of scale. This century, the focus is on micro devices like lab-on-a-chip and high speed computer processors that deliver their product directly to the consumer. There are significant obstacles facing this new technology. Mixing is reduced due to laminar flow, and a large amount of energy is needed to move the fluid through such small devices. Particles are often added to improve mixing and heat transfer, but their presence adds to the energy requirements. This study will help us overcome these challenges. Read moreRead less
Microdynamic modelling and analysis of gas fluidization of particle mixtures. The project aims to develop a comprehensive understanding of the mechanisms governing the particle-fluid flow in gas fluidization of mixtures of particles of different sizes. This will be achieved through detailed analysis of the particle-particle and particle-fluid interactions on the basis of the microdynamic or particle scale results generated by the newly developed discrete simulation technique. The microscopic fin ....Microdynamic modelling and analysis of gas fluidization of particle mixtures. The project aims to develop a comprehensive understanding of the mechanisms governing the particle-fluid flow in gas fluidization of mixtures of particles of different sizes. This will be achieved through detailed analysis of the particle-particle and particle-fluid interactions on the basis of the microdynamic or particle scale results generated by the newly developed discrete simulation technique. The microscopic findings will be implemented in the macroscopic, continuum-based modelling and tested by comparing numerical and experimental results. It will significantly enhance the present capability of modelling particle-fluid flow in gas fluidization which is widely used in mineral/chemical industries.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
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
Granular dynamics: from discrete simulation towards continuum modelling. The project aims to develop a general averaging theory to link discrete to continuum description of granular dynamics and a comprehensive understanding of the underlying physics. This will be achieved through detailed analysis of the particle-particle and particle-wall interactions at both microscopic and macroscopic levels, supported by the newly developed averaging theory and novel discrete particle simulation. The result ....Granular dynamics: from discrete simulation towards continuum modelling. The project aims to develop a general averaging theory to link discrete to continuum description of granular dynamics and a comprehensive understanding of the underlying physics. This will be achieved through detailed analysis of the particle-particle and particle-wall interactions at both microscopic and macroscopic levels, supported by the newly developed averaging theory and novel discrete particle simulation. The results, in terms of constitutive relations and boundary conditions, will be implemented in continuum-based process modelling and tested by comparing numerical and experimental results via typical case studies. It will significantly enhance the present capability of modelling granular flow that is widely encountered in many industries and in nature.Read moreRead less
Interstellar Gas Dynamics. The conversion of interstellar gas into stars is a key process in the life-history of galaxies and the formation of planetary systems. Star formation takes place within a heterogeneous, dynamic cloud, and entails a million-fold contraction controlled by a complex interplay between gravity, magnetic forces, ionisation balance, chemical reactions and particles of interstellar dust. Previous modelling has adopted inappropriate approximations for the evolution of the mag ....Interstellar Gas Dynamics. The conversion of interstellar gas into stars is a key process in the life-history of galaxies and the formation of planetary systems. Star formation takes place within a heterogeneous, dynamic cloud, and entails a million-fold contraction controlled by a complex interplay between gravity, magnetic forces, ionisation balance, chemical reactions and particles of interstellar dust. Previous modelling has adopted inappropriate approximations for the evolution of the magnetic field. This research will bring a rigorous treatment of magnetic diffusion to bear on the theory of cloud evolution, shock waves, star formation and protoplanetary discs.
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