Projects per year

## Personal profile

### Personal Statement

M.Z. Afsar holds a Masters in Aeronautical Engineering (2003) from the University of Bristol & for which he received the Royal Aeronautical Society Award. His research career began in the summer of 2002 when, still as an undergraduate, he received a Research Assistantship from the Department of Applied Physics at Yale University working as an experimentalist in laser diagnostics. He holds a Ph.D. from the University of Cambridge (2009) in jet noise modeling and received a number of research fellowships thereafter working at the NASA Glenn Research Center with Drs. Marvin Goldstein & S. J. Leib on a variety of problems in aero-acoustics, 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 methods; Aeroacoustics; Turbulence theory & modeling, boundary layer transition and Applied Mathematics.

### 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

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## Projects 2017 2018

- 3 Finished

## Jet noise modeling in heated and isothermal supersonic air jets

Afsar, M., Sescu, A. & Sassanis, V.

1/01/18 → 31/05/18

Project: Non-funded project

## Comparison of trailing edge noise model with Large-Eddy Simulations

Afsar, M. & Sescu, A.

1/11/17 → 1/11/18

Project: Non-funded project

## Research Output 2016 2018

## Hampering Görtler vortices via optimal control in the framework of nonlinear boundary region equations

Sescu, A. & Afsar, M., 14 Apr 2018, (Accepted/In press) In : Journal of Fluid Mechanics. 36 p.Research output: Contribution to journal › Article

## Effect of de-correlating turbulence on the low frequency decay of jet-surface interaction noise in sub-sonic unheated air jets using a CFD-based approach

Afsar, M., Leib, S. & Bozak, R., 6 Jan 2017, In : Journal of Sound and Vibration. 386, p. 177–207 30 p.Research output: Contribution to journal › Article