From Jet Engines to the Human Body: Open-Source Numerical Modelling for
Thermoacoustics and Beyond

by Ekrem Ekici
(Department of Mechanical Engineering, Boğaziçi University)

Date : October 2, 2026 (Friday)
Time : 14:00-15:00
Room: VYKM-2

Abstract:
Open-source software is increasingly central to reproducible and
transferable research in computational mechanics. From the outset of
this research, all numerical tools have been built on an open-source
finite element method (FEM) stack, FEniCSx/DOLFINx, and designed to run
in parallel. This talk follows that stack from its origin in aero-engine
combustion to applications in the human body. The starting point is
thermoacoustic instability, a long-standing challenge in gas turbine
design.

Modern gas turbine combustors are susceptible to oscillations caused by
the interaction between acoustic pressure waves and the flame. If these
acoustic pressure waves are sufficiently in phase with the heat release
rate, the oscillations can grow significantly, which may cause extra
heat transfer, excessive noise, or even failure of the engine. We use
the thermoacoustic Helmholtz equation to model this instability problem
as an eigenvalue problem. The eigenfrequency and the growth rate of the
system are obtained using helmholtz-x, our open-source parallelized
Helmholtz solver. The combustor geometry is parametrized using free-form
deformation (FFD). We then use the FFD geometry, define the system
parameters and impose the acoustic boundary conditions to calculate the
eigenvalue and eigenvector of the problem. Next, we use adjoint methods
to calculate the shape derivatives of the unstable eigenvalue with
respect to the FFD control points. According to the gradients, we make
small modifications to the control points to reduce the growth rate.
These results show this method's potential to reduce combustion
instability in industrial gas turbine combustors.

This same open-source FEM stack has since been extended beyond
thermoacoustics: to ear canal acoustics, directly inheriting
helmholtz-x; to wound healing, modelled through nonlinear diffusion; and
to topology optimization of prosthetic feet, based on linear elasticity.
Together, these applications show how a single open-source numerical
foundation can reach from jet engines to the human body.

Short Bio:
Ekrem Ekici is an Assistant Professor in the Department of Mechanical
Engineering at Boğaziçi University. He received his PhD in Engineering
Science from the University of Cambridge in 2024, and his MSc in
Advanced Mechanical Engineering from the University of Birmingham in
2020. Before joining Boğaziçi, he was a Postdoctoral Fellow at King Fahd
University of Petroleum and Minerals. His research focuses on numerical
optimization using open-source software such as FEniCSx and its
components. His work in acoustics covers a wide range of applications,
from jet engines to bioacoustics.