Background

Dr Umair Ahmed obtained his undergraduate degree in mechanical engineering with 1st class Hons from the University of Manchester in 2010, which was followed by a PhD in mechanical engineering with an emphasis on Computational Fluid Dynamics (CFD) and computational combustion at the University of Manchester in 2014. He joined Newcastle University as a Lecturer in 2019, prior to this he has worked as a Research Associate at Newcastle University (2017-2019) and as a Research Associate and Teaching Fellow at the University of Manchester (2013-2017). 

Dr Ahmed's research interests include Computational Fluid Dynamics (CFD), with a focus on turbulence, heat transfer, computational combustion, multiphase flows and non-Newtonian fluid flows. As part of his research he has been involved in several projects which range from Large Eddy Simulations (LES) of full scale rotating marine turbines, modelling of non-Newtonian fluids in industrial scale mixers, Reynolds Averaged Navier-Stokes (RANS) simulation of premixed turbulent combustion to Direct Numerical Simulation (DNS) of turbulence and combustion in free shear and wall bounded flows. Furthermore, he has also been involved in developing mathematical models for turbulence and combustion under the RANS framework.

Areas of expertise

• Computational Fluid Dynamics (CFD)
• Direct Numerical Simulation (DNS) of turbulence, scalar mixing, heat transfer and combustion
• Modelling and Simulation of turbulence, heat transfer and combustion under Large Eddy Simulation (LES) and Reynolds Averaged Navier Stokes (RANS) frameworks
• Heat Transfer modelling
• Numerical modelling of Non-Newtonian fluid flows

Research

• Computational Fluid Dynamics (CFD).
• Direct Numerical Simulation (DNS) of turbulence, heat transfer and combustion.
• Modelling and Simulation of turbulence, heat transfer and combustion under Large Eddy Simulation (LES) and Reynolds Averaged Navier Stokes (RANS) frameworks
• Heat Transfer modelling.
  
• Numerical modelling of Non-Newtonian fluid flows.
• Developing new algorithms and open source CFD software for high performance computing (HPC) platforms.

Teaching

Current Teaching:

• MEC3014: Computational Modelling 
• MEC8043: Software in the Professional Engineering Context
• MEC3098: Mechanical Engineering Project
• MEC8095: MSc Project

Publications

• Ahmed U, Herbert A, Chakraborty N, Klein M. On the validity of Damköhler’s second hypothesis in statistically planar turbulent premixed flames in the thin reaction zones regime. Proceedings of the Combustion Institute 2020. In Press.
• Konstantinou I, Ahmed U, Chakraborty N. Effects of Fuel Lewis Number on the Near-wall Dynamics for Statistically Planar Turbulent Premixed Flames Impinging on Inert Cold Walls. Combustion Science and Technology 2020, epub ahead of print.
• Herbert A, Ahmed U, Chakraborty N, Klein M. Applicability of extrapolation relations for curvature and stretch rate dependences of displacement speed for statistically planar turbulent premixed flames . Combustion Theory and Modelling 2020, epub ahead of print.
• Malkeson SP, Ahmed U, Pillai AL, Chakraborty N, Kurose R. Evolution of Surface Density Function in an open turbulent jet spray flame. Flow, Turbulence and Combustion 2020, epub ahead of print.
• Ozel-Erol G, Ahmed U, Chakraborty N. Flame self-interactions in globally stoichiometric spherically expanding flames propagating into fuel droplet-mists. Proceedings of the Combustion Institute 2020, (ePub ahead of Print).
• Ahmed U, Chakraborty N, Klein M. Scalar gradient and strain rate statistics in oblique premixed flame-wall interaction within turbulent channel flows. Flow, Turbulence and Combustion 2020, (ePub ahead of Print).
• Brearley P, Ahmed U, Chakraborty N, Klein M. Scaling of Second-Order Structure Functions in Turbulent Premixed Flames in the Flamelet Combustion Regime. Fluids 2020, 5(2), 89.
• Ahmed U, Pillai AL, Chakraborty N, Kurose R. Surface density function evolution and the influence of strain rates during turbulent boundary layer flashback of hydrogen-rich premixed combustion. Physics of Fluids 2020, 32(5), 055112.
• Ahmed U, Apsley D, Stallard T, Stansby P, Afgan I. Turbulent length scales and budgets of Reynolds stress-transport for open-channel flows; Friction Reynolds numbers (Reτ ) = 150, 400 & 1020. Journal of Hydraulic Research 2020, ePub ahead of print.
• Brearley P, Ahmed U, Chakraborty N, Lipatnikov A. Statistical behaviours of conditioned two-point second-order structure functions in turbulent premixed flames in different combustion regimes. Physics of Fluids 2019, 31(11), 115109.
• Ahmed U, Chakraborty N, Klein M. On the stress-strain alignment in premixed turbulent flames. Scientific Reports 2019, 9, 5092.
• Konstantinou I, Ahmed U, Chakraborty N, Klein M. Statistics of turbulence during head-on quenching of premixed turbulent combustion in boundary layers. In: International Workshop on Clean Combustion: Principles and Applications. 2019, Darmstadt.
• Ahmed U, Chakraborty N, Klein M. Scalar gradient and strain rate statistics in oblique premixed flame-wall interaction with turbulent boundary layers. In: International Workshop on Clean Combustion: Principles and Applications. 2019, Darmstadt.
• Ahmed U, Pillai A, Chakraborty N, Kurose R. Statistical behaviour of turbulent kinetic energy transport in boundary layer flashback of hydrogen-rich premixed combustion. Physical Review Fluids 2019, 4, 103201.
• Ahmed U, Klein M, Chakraborty N. Oblique flame-wall interaction in premixed turbulent combustion under isothermal and adiabatic wall boundary conditions. In: 27th International Colloquium on Dynamics of Explosions and Reactive Systems. 2019, Beijing, China: Institute for Dynamics of Explosions and Reactive Systems.
• Konstantinou I, Ahmed U, Chakraborty N. Influence of fuel Lewis number on flame-wall interaction for impinging turbulent premixed flames. In: 27th International Colloquium on Dynamics of Explosions and Reactive Systems. 2019, Beijing, China: Institute for Dynamics of Explosions and Reactive Systems.
• Ahmed U, Pillai AL, Chakraborty N, Kurose R. Mean behaviour of flame displacement speed in boundary layer flashback of hydrogen-rich premixed turbulent combustion. In: 12th Asia-Pacific Conference on Combustion (ASPACC 2019). 2019, Fukuoka: Combustion Institute.
• Ahmed U, Pillai A, Kurose R, Chakraborty N. Statistical behaviour of turbulent kinetic energy transport in boundary layer flashback of hydrogen-rich premixed flames. In: 11th Mediterranean Combustion Symposium. 2019, Tenerife, Spain: International Centre for Heat and Mass Transfer.
• Konstantinou I, Ahmed U, Klein M, Chakraborty N. Near-wall behaviour of turbulence in flame-wall interaction of premixed turbulent combustion in boundary layers. In: 9th European Combustion Meeting (ECM 2019). 2019, Lisboa, Portugal.
• Turquand d'Auzay C, Ahmed U, Pillai A, Chakraborty N, Kurose R. Statistics of progress variable and mixture fraction gradients in an open turbulent jet spray flame. Fuel 2019, 247, 198-208.
• Ahmed U, Chakraborty N, Klein M. Insights into the bending effect in premixed turbulent combustion using the Flame Surface Density transport. Combustion Science and Technology 2019, Epub ahead of print.
• Ahmed U, Turquand d'Auzay C, Muto M, Chakraborty N, Kurose R. Statistics of reaction progress variable and mixture fraction gradients of a pulverised coal jet flame using Direct Numerical Simulation data. Proceedings of the Combustion Institute 2018, 37(3), 2821-2830.
• Ahmed U, Doan NAK, Lai J, Klein M, Chakraborty N, Swaminathan N. Multiscale analysis of head-on quenching premixed turbulent flames. Physics of Fluids 2018, 30(10), 105102.
• Ahmed U, Chakraborty N, Klein M. Stress-strain alignment in premixed turbulent combustion. In: 12th International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurement (ETMM12). 2018, Montpelier, France.
• Ahmed U, Lai J, Doan NAK, Klein M, Chakraborty N, Swaminathan N. Effects of detailed chemistry on multiscale analysis of head-on quenching in premixed turbulent combustion. In: 12th International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurement (ETMM12). 2018, Montpelier, France.
• Michael V, Bagkeris I, Ahmed U, Prosser R, Kowalski A. Large-eddy simulation of non-circular jet flow in a pilot-scale inline high-shear static mixer. In: 12th International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurement (ETMM12). 2018, Montpelier, France.
• Ahmed U, Michael V, Hou R, Mothersdale T, Prosser R, Kowalski A, Martin P. An energy transport based evolving rheology in high-shear rotor–stator mixers. Chemical Engineering Research and Design 2018, 133, 398-406.
• Ahmed U, Prosser R. A Posteriori Assessment of Algebraic Scalar Dissipation Models for RANS Simulation of Premixed Turbulent Combustion. Flow, Turbulence and Combustion 2018, 100(1), 39-73.
• Ahmed U, Prosser R, Kowalski A. An energy transport based evolving rheology. In: 9th International Symposium on Mixing in Industrial Processes. 2017, Birmingham, UK.
• Ahmed U, Apsley D, Afgan I, Stallard T, Stansby P. Fluctuating loads on a tidal turbine due to velocity shear and turbulence: comparison of CFD with field data. Renewable Energy 2017, 112, 235-246.
• Ahmed U, Nivarti G, Zimon M, Prosser R, Cant R. The role of pressure Hessian in premixed turbulent combustion. In: Sixteenth SIAM International Conference on Numerical Combustion. 2017, Orlando, FL, USA: SIAM.
• Ahmed U, Prosser R. Modelling flame turbulence interaction in RANS simulation of premixed turbulent combustion. Combustion Theory and Modelling 2016, 20(1), 34-57.
• Ahmed U, Afgan I, Apsley D, Stallard T, Stansby P. CFD Simulations of a full-scale tidal turbine: Comparison of LES and RANS with field data. In: 11th European Wave and Tidal Energy Conference. 2015, Nantes, France.
• Ahmed U, Afgan I, Apsley D, Stallard T, Stansby P. Large Eddy Simulations to represent a full-scale tidal stream flow and turbine. In: Oxford Tidal Energy Workshop. 2015, Oxford, UK.
• Afgan I, Ahmed U, Apsley D, Stallard T, Stansby P. CFD Simulations of a Full-Scale Tidal Stream Turbine: Comparison Between Large-Eddy Simulations and Field Measurements. UK: Energy Technologies Institute, 2014. MD1.4.
• Ahmed U, Prosser R, Revell A. Towards the development of an evolution equation for flame turbulence interaction in premixed turbulent combustion. Flow, Turbulence and Combustion 2014, 93(4), 637-663.
• Ahmed U, Prosser R, Revell A. An evolution equation for flame turbulence interaction in premixed turbulent combustion. ERCOFTAC Bulletin 2014, 96.
• Ahmed U, Prosser R, Revell A. A transport equation for flame turbulence interaction in premixed turbulent combustion. In: European Combustion Meeting. 2013, Lund, Sweden.