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, scalar mixing, 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

• Computational Fluid Dynamics (CFD).
• Direct Numerical Simulation (DNS) of turbulence, scalar mixing, heat transfer and combustion.
• Modelling and simulation of turbulence, scalar mixing, 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.

Current Teaching:

• MEC3028: Computational Heat & Fluid Flow 
• MEC8043: Software in the Professional Engineering Context
• MEC3098: Mechanical Engineering Project
• MEC8095: MSc Project

• Brearley P, Ahmed U, Chakraborty N. A priori Direct Numerical Simulation analysis of the closure of cross-scalar dissipation rate of reaction progress variable and mixture fraction in turbulent stratified flames. Flow, Turbulence and Combustion 2022, (ePub ahead of Print).
• Chakraborty N, Ahmed U, Klein M, Im HG. Alignment statistics of pressure Hessian with strain rate tensor and reactive scalar gradient in turbulent premixed flames. Physics of Fluids 2022, 34(6), 065120.
• Awad HS, Abo-Amsha K, Ahmed U, Klein M, Chakraborty N. Assessment of Damköhler’s hypotheses in the thin reaction zones regime using multi-step chemistry Direct Numerical Simulations of statistically planar turbulent premixed flames. Physics of Fluids 2022, 34(5), 055120.
• Ghai SK, Ahmed U, Chakraborty N, Klein M. Entropy generation during head-on interaction of premixed flames with inert walls within turbulent boundary layers. Entropy 2022, 24(4), 463.
• Varma AR, Ahmed U, Chakraborty N. Effects of buoyancy on turbulent scalar flux closure for turbulent premixed flames in the context of Reynolds Averaged Navier–Stokes simulations. Combustion Theory and Modelling 2022, Epub ahead of print.
• Lai J, Ahmed U, Klein M, Chakraborty N. A comparison between head-on quenching of stoichiometric methane-air and hydrogen-air premixed flames using Direct Numerical Simulations. International Journal of Heat and Fluid Flow 2022, 93, 108896.
• Brearley P, Ahmed U, Chakraborty N. Scalar Forcing Methodology for Direct Numerical Simulations of Turbulent Stratified Mixture Combustion. Flow, Turbulence and Combustion 2022, (ePub ahead of Print).
• Varma AR, Ahmed U, Chakraborty N. Effects of Body Forces on Turbulent Kinetic Energy Transport in Premixed Flames. Flow, Turbulence and Combustion 2022, epub ahead of print.
• Chakraborty N, Herbert A, Ahmed U, Im HG, Klein M. Assessment of extrapolation relations of displacement speed for detailed chemistry Direct Numerical Simulation database of statistically planar turbulent premixed flames. Flow, Turbulence and Combustion 2021, (ePub ahead of Print).
• Chakraborty N, Kasten C, Ahmed U, Klein M. Evolutions of strain rate and dissipation rate of kinetic energy in turbulent premixed flames. Physics of Fluids 2021, 33, 125132.
• Ahmed U, Chakraborty N, Klein M. Influence of thermal wall boundary condition on scalar statistics during flame-wall interaction of premixed combustion in turbulent boundary layers. International Journal of Heat and Fluid Flow 2021, 92, 108881.
• Awad H, Abo-Amsha K, Ahmed U, Chakraborty N. Comparison of the reactive scalar gradient evolution between homogeneous MILD combustion and premixed turbulent flames. Energies 2021, 14(22), 7677.
• Umair A, Chakraborty N, Klein M. Effects of Turbulent Boundary Layer on the Near-Wall Flame Dynamics in the Case of Adiabatic Walls. In: Engineering, Turbulence, Modelling and Measurements (ETMM13). 2021, Rhodes, Greece.
• Lai J, Ahmed U, Klein M, Chakraborty N. A comparison between head-on quenching of turbulent methane-air and hydrogen-air flames using detailed chemistry Direct Numerical Simulations. In: Engineering, Turbulence, Modelling and Measurements (ETMM13). 2021, Rhodes, Greece: ERCOFTAC.
• Varma A, Ahmed U, Chakraborty N. Effects of buoyancy on turbulent kinetic energy transport in turbulent premixed flames. In: Engineering, Turbulence, Modelling and Measurements (ETMM13). 2021, Rhodes, Greece: ERCOFTAC.
• Keil FB, Amzehnhoff M, Ahmed U, Chakraborty N, Klein M. Comparison of flame propagation statistics based on DNS of simple and detailed chemistry. Part 2: Influence of choice of reaction progress variable. Energies 2021, 14(18), 5695.
• Keil FB, Amzehnhoff M, Ahmed U, Chakraborty N, Klein M. Comparison of flame propagation statistics extracted from DNS based on simple and detailed chemistry Part 1: Fundamental flame turbulence interaction. Energies 2021, 14(17), 5548.
• Varma A, Ahmed U, Klein M, Chakraborty N. Effects of turbulent length scale on the bending effect of turbulent burning velocity in premixed turbulent combustion. Combustion and Flame 2021, 233, 111569.
• Ahmed U, Chakraborty N, Klein M. Assessment of Bray Moss Libby formulation for premixed flame-wall interaction within turbulent boundary layers: Influence of flow configuration. Combustion and Flame 2021, 233, 111575.
• Ahmed U, Chakraborty N, Klein M. Influence of wall boundary conditions on premixed flame-wall interaction in turbulent boundary layers. In: European Combustion Meeting. 2021, Naples, Italy.
• Brearley P, Ahmed U, Chakraborty N. A-priori Direct Numerical Simulation evaluation of the cross-scalar dissipation rate of reaction progress variable and mixture fraction in turbulent stratified flames. In: European Combustion Meeting. 2021, Naples, Italy (Virtual): ECM.
• Awad H, Aboo Amsha K, Ahmed U, Chakraborty N. Comparison of Surface Density Function (SDF) statistics between MILD and premixed turbulent combustion. In: European Combustion Meeting. 2021, Naples, Italy: ECM.
• Varma A, Ahmed U, Chakraborty N. Effects of body forces on the statistics of flame surface density and its evolution in statistically planar turbulent premixed flames. Flow, Turbulence and Combustion 2021, epub ahead of print.
• Kasten C, Ahmed U, Klein M, Chakraborty N. Principal strain rate evolution within turbulent premixed flames for different combustion regimes. Physics of Fluids 2021, 33(1), 015111.
• Malkeson SP, Ahmed U, Pillai A, Chakraborty N, Kurose R. Flame self-interactions in an open turbulent jet spray flame. Physics of Fluids 2021, 33(3), 035114.
• Varma AR, Ahmed U, Chakraborty N. Effects of body forces on vorticity and enstrophy evolutions in turbulent premixed flames. Physics of Fluids 2021, 33(3), 035102.
• 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 2021, 59(1), 36-50.
• 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 2021, 38(2), 3039-3047.
• 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 2021, 38(2), 3351-3359.
• 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 2021, 193(2), 235-265.
• 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 2021, 106, 701-732.
• Tan G, Ahmed U, Wang L, Chakraborty N. Quantification of the flame structure at multi-scale levels. Physics of Fluids 2020, 32(12), 125110.
• Brearley P, Ahmed U, Chakraborty N. The relation between flame surface area and turbulent burning velocity in statistically planar turbulent stratified flames. Physics of Fluids 2020, 32(12), 125111.
• Malkeson SP, Ahmed U, Turquand d'Auzay C, Pillai AL, Chakraborty N, Kurose R. Displacement speed statistics in an open turbulent jet spray flame. Fuel 2020, 286(Part 1), 119242.
• 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, 24(6), 1021-1038.
• 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 2021, 106, 207-229.
• 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.
• 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, Chakraborty N, Kurose R. 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, 191(5-6), 898-920.
• 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 2019, 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: Pacific Northwest National Laboratory (PNNL).
• 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.