Farhad Hasanli
Computational aerodynamics · Texas A&M
PhD candidate in Ocean Engineering at Texas A&M. My research is wall-modeled large-eddy simulation and subgrid-scale closures for compressible external aerodynamics, implemented in PyFR. Longer term, I'd like to work on launch vehicles.
Resolving every eddy on a full-scale aircraft scales roughly as the cube of the Reynolds number. At flight conditions that is well beyond available computing, and likely to stay that way. So practical aerodynamic simulation depends on turbulence models — and the flows where those models are least reliable, such as separation, buffet, and transition, tend to be the ones that matter most for design.
Near a surface, the eddies carrying most of the stress scale with distance from the wall, so resolving them takes up the bulk of the cost. A wall model replaces the inner layer with a reduced problem that supplies the wall stress back to the LES. I work on ODE-based formulations for compressible flow — equilibrium and non-equilibrium — implemented in PyFR, a high-order flux reconstruction solver.
Above the grid cutoff, the model has to represent what the unresolved motions do to the resolved ones. Common eddy-viscosity closures assume the cascade is in equilibrium, which many flows of practical interest aren't. I'm looking at closures that relax that assumption, and at when a high-order scheme's own numerical dissipation already does much of the job.
Before Texas A&M I did an MS in Aerospace Engineering at the University of Illinois Urbana-Champaign, where I wrote Prandtl — a high-order discontinuous Galerkin spectral element solver built on MFEM, with subcell-volume-based shock capturing. My undergraduate degree is in Mechanical Engineering from KAIST, with a minor in Aerospace Engineering.
Building a solver end to end is where most of what I know about these methods came from — particularly about how they fail.
A lot of what makes reusable launch vehicles difficult is fluid dynamics — reentry heating, propulsive deceleration, control in regimes where flight data is thin and wind tunnels don't reach. Those are cases where simulation has to stand in for testing, which is more or less the same problem I'm working on now with lower stakes.
That's the direction I'd like to end up in, whether by joining people already building or by building something myself.
Get in touch
Papers, code, and notes are on the research site. Email is the best way to reach me.