Professor Gregory Sheard
Professor Gregory Sheard
My research is concerned with the stability of fluid (liquid or gas) flows. Fluid flows can range from stable, smooth, laminar flows to vigorously agitated turbulent flows, depending on the speeds and scales involved, with vastly different properties exhibited in each state. For engineers to reliably harness laminar or turbulent flows, it is crucial to understand how, when and why a laminar flow destabilizes and succumbs to turbulence: this is the nexus of my research.
I specialise in magnetohydrodynamics (the flow-induced interaction between electrically conducting fluids and magnetic fields), analysis of the stability of flows, bluff body flows (flows around obstacles, underpinning much of aerodynamics and wind engineering), and natural convection (flows driven by buoyancy differences due to heating, salinity, etc.).
A key research tool within my group is an advanced in-house numerical code for the simulation of two- and three-dimensional incompressible fluid flows based on the spectral-element method. Spectral-element methods combine the flexibility of finite-element approaches towards discretising complex flow domains into a grid of discrete elements with the exceptional convergence properties of spectral methods. This code implements features including a linearised solver enabling linear stability and transient growth analysis, quasi-two-dimensional and three-dimensional magnetohydrodynamics simulation, plus natural convection and heat transfer simulation capabilities.
Qualifications
- Doctor of Philosophy, Monash University
- Bachelor of Mechanical Engineering (hons), Monash University
Prizes, honours and awards
- 2020: Invited Speaker – 25th International Congress of Theoretical and Applied Mechanics (ICTAM), Milan, Italy, 23-28 August 2020 (postponed to 2021 due to COVID-19).
- 2020: Chair, Fluid Dynamics Program Committee, XXXII IUPAP Conference on Computational Physics, Coventry, England, 2-6 August 2020 (postponed to 2021 due to COVID-19).
- 2018: Media – ARC DP15 lung airflow research in collaboration with Monash Cave2 features on Ten Network Australia television program “Scope”
- 2017: Research featured on cover of volume 822 of top journal, Journal of Fluid Mechanics.
- 2016: “Best Paper Award” – Senior author on paper delivered at the Fifth International Conference on Advances in Civil, Structural and Mechanical Engineering
- 2015: Chair and organiser, The 9th Australasian Natural Convection Workshop, December 2015
- 2015: Editor, 9th Australasian Natural Convection Workshop Program and Book of Abstracts
- 2015: Featured twice on American Institute of Physics “Research Highlights from Physics of Fluids”
- 2013: Invited lecture: Australian Rheological Society, 2013 Lecture Series.
- 2012: “Best student paper award” Senior author and supervisor of prizewinning paper at the 9th International Conference on CFD in the Minerals and Process Industries
- 2012: Co-author on paper awarded the IOP Science “Measurement Science & Technology Outstanding Paper Award” selected from 400 published papers.
- 2012: Inducted into the Monash University National Competitive Fellowships Incubator Program
- 2011: The Visualization Society of Japan (VSJ) Award for Excellent Visualization in 2011, for Ng, I., Kumar, V., Sheard, G.J., Hourigan, K. & Fouras, A. 2010 Surface topography of jet shock cells in a hydraulic analogy. Journal of Visualization 13 (3), 175-176.
- 2010: Invited Lecture at the CSIRO Computational & Simulation Sciences Annual Conference & Workshops, 16-18 March 2012, Melbourne, Australia.
- 2010: Completed the Group of 8 Future Research Leaders program, Monash University.
- 2009: Chair of Judging Committee & member of Organising Committee: Seventh International Conference on Computational Fluid Dynamics in the Minerals and Process Industries, Melbourne, Australia, 9-11 December 2009.
- 2009: Invited journal paper contributed to a Special Issue published in the Journal of Engineering Mathematics, on the topic “Modelling Cardiovascular Haemodynamics in Health and Disease,” vol. 64, issue 4, 2009.
- 2006: Chair of opening keynote lecture & Organiser of the Bio-Engineering Mini-Symposium conducted as part of the Fifth International Conference on Computational Fluid Dynamics in Process Industries, Melbourne, Australia, 13-15 December 2006.
- 2005-2007: ARC Australian Postdoctoral Fellowship
- 2005: Young Researcher Fellowship Award, Third MIT Conference on Computational Fluid and Solid Mechanics, Massachusetts Institute of Technology, Cambridge, MA, USA
- 2005: Kenneth Hunt Medal, Faculty of Engineering, Monash University
- 2005: Mollie Holman Doctoral Medal, Monash University
- 2003: Postgraduate Publication Award, Australian Commonwealth Government
- 2000: Australian Postgraduate Award, Australian Commonwealth Government
Research Projects
Current projects
Hybrid imaging/modelling: A new paradigm for understanding the lung.
Our lungs are essential to sustain our lives, yet the details of lung biomechanics are barely understood because the available tools: imaging, modelling and simulation have significant limitations. Imaging is largely limited to providing structural information; simulation is severely restricted by a lack of validation; and inverse modelling is critically hampered by a lack of spatially resolved inputs. Our multidisciplinary team is uniquely positioned to solve these problems through the hybridization of our world-leading functional lung imaging
technology with state-of-the-art modelling, providing for the first time, the capacity to see details with the
resolution of imaging, richness of modelling and reliability of the finest measurements.
The elusive upper bound of heat transfer in horizontal convection.
The question as to whether lateral variation in global ocean buoyancy resulting from low solar radiation near
the poles and higher temperatures in the tropical regions (known as horizontal convection) is a driver for global ocean currents is critical to our understanding of this complex and delicate system that maintains Earth’s temperate climate. This question hinges on the relationship between heat transport and strength of
buoyancy forcing towards global scales: this project proposes a landmark experimental effort supported by
detailed simulations to probe the ultimate regime of heat transport in horizontal convection. The project will inform the direction of future ocean and climate modelling efforts to the benefit of humanity.
Past projects
Methodologies for resolving high Rayleigh number transitions in convection and elucidating instabilities in polar vortices.
Although the behaviour of the rotating air masses at Earth’s poles is poorly understood, these polar vortices are a driving force in Arctic and Antarctic region climate events and may explain certain periodic variations in Australian climate. By developing a new technique for modeling convection flows, this in-depth examination will contribute to the modelling of these vortices for improved prediction of current Australian and global weather patterns. In addition, an enhanced knowledge of polar vortices is critical in correctly predicting the future evolution of our climate. These outcomes are of considerable importance to Australia’s agricultural sector, water planning and bushfire management efforts.
ScorpTech Venom Platinum Nvidia CUDA GPU computing machine.
Supersonic flow past micro-scale particles: Industrial applications.
Droplet-based materials processing is a method currently used in the manufacture of light-weight, high-strength metal alloys for use in a wide range of industries. Critical to the successful use of such processes is an accurate knowledge of the cooling rate of micro-sized droplets within high speed flows, with velocities greater than the speed of sound. Current understanding of the cooling rate relies upon empirical knowledge. This project intends to provide world first, highly-accurate numerical and experimental research to determine the thermo- and fluid-dynamics for flows around micro-scale spheres. The overall aim of this project is to determine an accurate model for the cooling rate of droplets in high-speed flows.
BenQ MP770 DLP Projector.
Tablet PC Student presentation platform.
Fluid Dynamics of Circulation: Focus on the Kidney.
High blood pressure is a major national health problem in Australia and is related to the development of heart disease. There is now compelling evidence for a crucial role of the kidney in the control of blood pressure. There are 3 features of the renal circulation that are unique to the kidney. These appear to be critical for the ability of the kidney to control blood pressure. Using laboratory models, a team of engineers and physiologists will investigate fluid flow within the renal circulation, focusing on these 3 unique aspects. We will use models of the renal circulation to study aspects of its control that cannot be studied in the kidney itself. It is expected that strategies will emerge to tackle the problem of hypertension.
See https://SheardLab.org/publications/ for my full list of publications.
ARC Discovery Project DP180102647
“Horizontal convection at ocean-relevant proportions” – $468,485 over 2018-2020
Investigators: Sheard, G.J.
Summary: This project aims to determine the role of buoyancy differences from solar radiation and vertical confinement. Flows created by lateral variation in heat or buoyancy are poorly understood when the horizontal length greatly exceeds the height, precisely the conditions relevant to industry and understanding the role of horizontal convection in Earth’s oceans and in turn the delicate current system that maintains Earth’s temperate climate. This project proposes computational and experimental efforts to probe the ultimate regime of heat transport in very shallow horizontal convection, benefiting humankind through improvements to future ocean and climate modelling efforts.
The Royal Society International Exchanges 2017/R1, Grant number IE170034
“Transition to quasi-two-dimensional turbulence” – £12,000 over 2017-2019
Investigators: Pothérat, A. & Sheard, G.J.
ARC Discovery Project DP150102920
“The elusive upper bound of heat transfer in horizontal convection” – $375,100 over 2015-2017
Investigators: Sheard, G.J.
Summary: The question as to whether lateral variation in global ocean buoyancy resulting from low solar radiation near the poles and higher temperatures in the tropical regions (known as horizontal convection) is a driver for global ocean currents is critical to our understanding of this complex and delicate system that maintains Earth’s temperate climate. This question hinges on the relationship between heat transport and strength of buoyancy forcing towards global scales; this project proposes a landmark experimental effort supported by detailed simulations to probe the ultimate regime of heat transport in horizontal convection. The project is expected to inform the direction of future ocean and climate modelling efforts to the benefit of humanity.
ARC Discovery Project DP150102240
“Hybrid imaging/modelling: A new paradigm for understanding the lung” – $334,400 over 2015-2017
Investigators: Fouras, A., Sheard, G.J. & Thompson, B.R.
Summary: Our lungs are essential to sustain our lives, yet the details of lung biomechanics are barely understood because the available tools, imaging, modelling and simulation have significant limitations. Imaging is largely limited to providing structural information; simulation is severely restricted by a lack of validation; and inverse modelling is critically hampered by a lack of spatially resolved inputs. The project’s multidisciplinary team is uniquely positioned to explore these problems through the hybridisation of world-leading functional lung imaging technology with state-of-the-art modelling. This project aims to provide, perhaps for the first time, the capacity to see details with the resolution of imaging, richness of modelling and reliability of the finest measurements.
ARC Discovery Project DP120100153
“Methodologies for resolving high Rayleigh number transitions in convection and elucidating instabilities in polar vortices” – $320,000 over 2012-2014
Investigators: Sheard, G.J.
Summary: This project will develop new methods for modeling complex rotating convection flows such as polar vortices found in the Antarctic atmosphere. This work has the potential to provide insight into important physical processes impacting Australian and global weather patterns, which is crucial for understanding the evolution of our climate.
ARC Discovery Project DP0665736
“Supersonic flow past micro-scale particles: Industrial applications” – $355,000 over 2006-2009
Investigators: Sheard, G.J., Carberry, J. & Ryan, K.
Summary: Droplet based materials processing has developed significantly over the last decade, with applications in a wide range of industries where high-strength, light-weight materials are critical. Our research will allow for continued progress of this method, by developing accurate models to predict the cooling rate throughout the process and hence the physical properties of the finished product. Development of this knowledge will allow for higher precision products to be produced and allow for new techniques to be developed. This information will allow for material processing in Australia to be maintained at world class levels, and for Australian industry to continue to lead the way in the production of technologically advanced materials.
ARC Discovery Project DP0555897
“Fluid dynamics of circulation: Focus on the kidney” – $338,000 over 2005-2007
Investigators: Hourigan, K., Anderson, W.P., Evans, R.G., Thompson, M.C., Denton, K.M., Kawahashi, M. & Sheard, G.J.
Summary: In Australia, about 30% of adults have hypertension, a major risk factor for heart disease, accounting for about 40% of all deaths. Problems in renal circulation are likely factors leading to hypertension. A detailed understanding of the renal circulation, of whose hydraulic characteristics we have limited knowledge, is required before we can cure or prevent hypertension. We will determine how the size, structure and geometry of the blood vessels influence the function of the kidney. This will lead to predictive models to aid the design and interpretation of physiological studies and the combat of hypertension. It will also help in the ongoing development of bioartificial kidneys to replace present dialysis systems.
Teaching Commitments
- ENG1040 - Engineering dynamics
- MAE5401 - Aerodynamics
- MAE2404 - Aerodynamics 1
- MAE3401 - Aerodynamics 2
- MEC5885 - Energy Efficiency and Sustainability Engineering
- MEC5881 - Engineering systems performance analysis