Thermoacoustic instabilities arise in combustion devices from the interaction of an unsteady heat release rate with acoustic waves. The feedback loop is closed by convected fluctuations, such as vortices, swirl or equivalence ratio fluctuations. Thermoacoustic instabilities impair the development of low-emission technologies such as lean combustion or H2-based fuels. Global linear methods — global stability, resolvent analysis, structural sensitivity — provide valuable tools for a monolithic approach to comprehensively investigating the flame-flow system. These methods pinpoint unstable phenomena and amplification mechanisms without the need for hybrid models.
This presentation will give an overview of the use of these methods for combustion-like cold flows and reactive flows, as well as perspectives for future developments.