Dr. Keith NGAN

Education
Ph.D. in Physics, The University of Toronto
Staff title
Assistant Professor

Dr. Keith Ngan obtained his B.Sc. in Physics and Chemistry from the University of British Columbia and his M.Sc. and Ph.D. in Physics from the University of Toronto. He was a postdoctoral fellow at the University of Chicago and a research associate at McGill University. He also worked as a senior research scientist in the numerical weather prediction division of the UK Met Office.

His research is focused on the fluid dynamics of the urban environment. It involves building-resolving numerical simulations via computational fluid dynamics, high-resolution atmospheric models, and mathematical modelling. Underlying themes include urban-mesoscale interactions, implications for air quality, and the application of techniques from applied mathematics and large-scale atmospheric dynamics. Recent applied projects include urban ventilation diagnostics and particulate matter in elevated walkway microenvironments. Recent theoretical projects include multiscale modelling of urban flow and dispersion, vortex dynamics for urban canopies, and scalar mixing in urban areas.

Other Information

Research Interests

  • Computational fluid dynamics

  • Environmental fluid mechanics

  • Numerical weather prediction

  • Turbulence

  • Urban meteorology

Recent Publications

  • KW Lo & K Ngan, 2019: Multiscale parameterisation of passive scalars via wavelet-based numerical homogenisation, Applied Mathematical Modelling, submitted.
  • G Duan & K Ngan, 2019:  “Sensitivity of turbulent flow around a 3-D building array to urban boundary-layer stability”, Journal of Wind  Engineering and Industrial Aerodynamics, 193, 103958, doi:10.1016/j.jweia.2019.103958.
  • G Duan, JG Jackson & K Ngan, 2019: Scalar mixing in an urban canyon, Environmental Fluid Mechanics, 19, 911-939, doi:10.1007/s10652-019-09690-0
  • GE Lau & K Ngan, 2018:  Analysing urban ventilation in building arrays with the age spectrum and mean age of pollutants, Building and Environment, 131, 288-305, doi:10.1016/j.buildenv.2018.01.010.
  • G Duan & K Ngan, 2018: Effects of time-dependent inflow perturbations on turbulent flow in a street canyon, Boundary-Layer Meteorology, 167, 257-284,   doi:10.1007/s10546-017-0327-1
  • KW Lo & K Ngan, 2017: Characterising urban ventilation and exposure using Lagrangian particles. Journal of Applied Meteorology and Climatology, 56, 1177-1194, doi:1175/JAMC-D-16-0168.
  • K Ngan & KW Lo, 2017: Linear error dynamics for turbulent flow in urban street canyons. Journal of Applied Meteorology and Climatology, 56, 1195-1208, doi:1175/JAMC-D-16-0173.1
  • K Ngan & KW Lo, 2016: Revisiting the flow regimes for urban street canyons using the numerical Green's function, Environmental Fluid Mechanics, 16, 313–334. doi:1007/s10652-015-9422-3
  • KW Lo & K Ngan, 2015: Characterising the pollutant ventilation characteristics of street canyons using the tracer age and age spectrum, Atmospheric Environment, 122, 611-621, DOI:1016/j.atmosenv.2015.10.023
  • K Ngan & KW Lo, 2015: Revisiting the flow regimes for urban street canyons using the numerical Green's function, Environmental Fluid Mechanics, 16, 313-334, DOI:1007/s10652-015-9422-3.
  • KW Lo & K Ngan, 2015: Predictability of turbulent flow in street canyons, Boundary-Layer Meteorology, 156, 191-210, DOI:10.1007/s10546-015-0014-z.

Current Projects

  • Ensemble box modelling of urban air pollution chemistry
  • Towards fast dynamical downscaling of mesoscale winds via building-resolving simulations
  • Predicting winds inside deep urban canopies using vortex dynamics
  • Applications of wavelets and multiscale modelling to urban canopy parameterisations

Positions available

Research opportunities are available for undergraduate and postgraduate students with interests in computational fluid dynamics, urban air quality, mathematical modelling or atmospheric science.

Research group

Current members

  • PhD students

    • Huanhuan Wang, Wanting Liu, Shang Gao

Former members

  • Postdoctoral fellows
    • Eden Furtak-Cole (PhD, Utah State University)
      Ghar Ek Lau (PhD, University of New South Wales)
      Gantuya Ganbat (PhD, Seoul National University)
      James G. Jackson (PhD University College London)
      Ka Wai Lo (PhD University of Illinois at Urbana-Champaign)
  • PhD students
    • Guangdong Duan (now at Kyoto University
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Staff Image
Keith Ngan
Contact Information
Office: YEUNG-B5436
Phone: +(852)-3442-6702
Fax: +(852)-3442-0688
Email: keith.ngan@cityu.edu.hk
Time slots for consultation
Research Interests
  • Computational fluid dynamics

  • Environmental fluid mechanics

  • Numerical weather prediction

  • Turbulence

  • Urban meteorology