Photo of Mohammed Afsar
  • United Kingdom

Accepting PhD Students

PhD projects

1. Jet noise modeling in non axi-symmetric air jets. 2. Large scale turbulence structures in compressible pipe flow. 3. Optimal control of vortices on aircraft wings using local surface deformations.

20162023
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Personal profile

Personal Statement

M.Z. Afsar holds a Masters in Aeronautical Engineering (2003) from the University of Bristol for which he received several commendations including the Royal Aeronautical Society Award. His research career began in the summer of 2002 when, still as an undergraduate, he obtained a Research Assistantship at the Department of Applied Physics of Yale University. Here he worked as an experimentalist, conducting Particle Image Velocimetry measurements in laminar flames using laser diagnostic tools. He holds a Ph.D. from the University of Cambridge (2009) in Engineering. His Ph.D. thesis was in Aeroacoustics and focused on Jet Noise Modeling. Following this, he received a number of research fellowships that allowed him to work at the NASA Glenn Research Center with world-famous Scientists, Drs. Marvin Goldstein and S. J. Leib, on a variety of problems in Aeroacoustics, Turbulence modeling and Rapid-distortion theory. Between July 2013--April 2016 he was based at Imperial College London (Dept. of Mathematics) working under the Laminar Flow Control platform grant with Professor X. Wu. Before joining Strathclyde University he was a visiting academic at Queen Mary University (in June-July 2016) and a remote visitor for the Stanford University Center for Turbulence Research summer program. His research interests include: Asymptotic analysis, Aeroacoustics, Turbulence theory & modeling, Boundary Layer Transition and Applied Mathematical methods.

Research Interests

Current research involves mathematical & numerical analysis of jet flow turbulence for Aero-acoustics problems such as jet noise and trailing/leading edge noise. I am also interested in mathematical modeling of boundary layer transition (receptivity and secondary instability theory) and wall turbulence.

Fields of scientific interest

Particular:

  • Secondary instabilities of streamwise vortex flows
  • Trailing/leading edge noise
  • Rapid-distortion theory of turbulence
  • Jet noise modeling in heated/isothermal flows
  • Kinematic and dynamic modeling of jet turbulence

General:

  • Perturbation methods in Applied Mathematics
  • Wiener-Hopf Technique
  • Complex analysis

 

Expertise & Capabilities

Main scientific results

  • We showed how optimally placed surface deformations hamper Gortler vortex growth rate and the temporal growth rates of resulting secondary instabilities (with A. Sescu, Mississippi State University).
  • We showed how non-parallel flow effects re-distribute the “two-peak” asymptotic structure of the Green’s function in the acoustic analogy approach so that a heated supersonic flow is quieter than an isothermal flow (with A. Sescu, Mississippi State University).
  • Showed how negative correlation in upstream turbulence affects the low frequency roll-off of the jet-surface interaction noise spectrum.
  • Working with NASA colleagues, we extending the Rapid-distortion theory of turbulence to compressible transversely sheared mean flows with physically realizable upstream boundary conditions (with M. E. Goldstein & S. J. Leib, NASA Glenn Research Center). This theory was applied to trailing edge noise problem.
  • We showed that non-parallel flow introduces a “two-peak” spatial structure in the Green’s function for predicting the low frequency jet noise in isothermal air jets under an appropriate asymptotic distinguished limit (with M. E. Goldstein, NASA Glenn Research Center & A. Sescu, University of Toledo).
  • Generalized spherical shell turbulence models to cylindrical shells in the axi-symmetric kinematic representation of the Reynolds stress auto-covariance tensor. This was validated against LES of high subsonic isothermal jet & PIV of incompressible water jet.

Teaching Interests

ME201 Aero Design  (Flight Mechanics)

ME405 Heat & Flow 4  (Heat transfer)

Academic / Professional qualifications

Education:

  • (Jan) 2004 – (Sept.) 2008:  Ph.D. in Aeronautical Engineering at Cambridge University, Department of Engineering. 

  • (Sept.) 1999 – 2003: First Class honors in Aeronautical Engineering M.Eng. at Bristol University, Department of Aeronautical Engineering.

Reviewer for:

  • Physics of Fluids
  • AIAA Journal
  • Journal of Fluid Mechanics

Member:

  • American Physical Society

Fingerprint Dive into the research topics where Mohammed Afsar is active. These topic labels come from the works of this person. Together they form a unique fingerprint.

Acoustics Engineering & Materials Science
Green's function Engineering & Materials Science
Turbulence Engineering & Materials Science
Vortex flow Engineering & Materials Science
Acoustic waves Engineering & Materials Science
Mach number Engineering & Materials Science
Boundary layers Engineering & Materials Science
turbulence Physics & Astronomy

Network Recent external collaboration on country level. Dive into details by clicking on the dots.

Projects 2017 2023

Research Output 2016 2020

Nonlinear centrifugal instabilities in curved free shear layers

Es-Sahli, O., Sescu, A. & Afsar, M., 10 Jan 2020. 19 p.

Research output: Contribution to conferencePaper

Open Access
File
shear layers
vortices
dump combustors
flow geometry
wall flow

Streaks in high-speed boundary layers: assessment via the full nonlinear boundary-region equations

Sescu, A., Afsar, M. & Hattori, Y., 10 Jan 2020. 14 p.

Research output: Contribution to conferencePaper

Open Access
File
Boundary layers
Vortex flow
Mach number
Hypersonic aerodynamics
Compressibility

Prizes

Global Engagements Fund (GEF) 2018

Mohammed Afsar (Recipient), 5 Jul 2018

Prize: Fellowship awarded competitively

Activities 2016 2020

  • 3 Invited talk
  • 1 Participation in workshop, seminar, course
  • 1 Journal peer review

An overview of the Rapid-distortion theory approach to jet surface interaction noise modelling

Mohammed Afsar (Speaker)
31 Jan 2020

Activity: Talk or presentation typesInvited talk

Sixteenth International Conference on Flow Dynamics, November 6 - 8, 2019, Sendai, Miyagi, Japan

Adrian Sescu (Participant), Mohammed Afsar (Participant), Shanti Bushan (Participant), Yuji Hattori (Participant), Makoto Hirota (Participant)
7 Nov 2019

Activity: Participating in or organising an event typesParticipation in workshop, seminar, course