In a recent publication titled Low-frequency streaky structures in turbulent hydrogen jet flames, FELiCS was used to reveal the mechanisms driving dominant heat-release fluctuations in hydrogen jet flames.
In an experimental campaign on a hydrogen multi-jet burner, optical PIV and OH* measurements identified pronounced heat-release fluctuations in the low- and intermediate-frequency range. With the help of a resolvent model based on the linearized Navier–Stokes equations, these structures were attributed to Kelvin–Helmholtz and lift-up type mechanisms at intermediate and low frequencies, respectively.
The low-frequency oscillations associated with the lift-up mechanism are particularly relevant from a technical perspective, as they give rise to energetic, streamwise-elongated structures that are likely important for combustion phenomena such as emission formation, thermoacoustic stability, and flashback safety.
The FELiCS software package was crucial for this study, providing the linear operators that formed the basis of the resolvent analysis and enabled the identification of the governing mechanisms.