Role of exceptional points in the thermoacosutic spectrum

Spectrum of a thermoacoustic system, and coalescence of two eigenvalues at an Exceptional Points.

 

Exceptional points (EPs) are ubiquitous in physics. They are peculiar degenerate eigenvalues that appear in the spectrum of any non-conservative system when one (or more) parameters are varied. At exceptional points, not only the eigenvalues, but also the two modeshapes coalesce. At EPs, eigenvalues have infinite sensitivities; moreover, the eigenvalue trajectories that form when a parameter is varied exhibit strong veering in the vicinity of an EP. This explains the high sensitivity of some thermoacoustic modes that has recently been discussed in the literature.

• Collaborators: Prof. Jonas Moeck (NTNU Trondheim), Dr. Georg Mensah

Related Publications

A. Orchini, C. Silva, G. Mensah, J. Moeck, "Thermoacoustic modes of intrinsic and acoustic origin and their interplay with exceptional points" Combustion and Flame, 2020, Vol. 211, pp. 83-95. [link]

A. Orchini, L. Magri, C. Silva, G. Mensah, J. Moeck, "Degenerate perturbation theory in thermoacoustics: high-order sensitivities and exceptional points" Journal of Fluid Mechanics, 2020, Vol. 903, pp. A37. [link]