Combustion noise comprises two components: direct combustion noise and indirect
combustion noise. The latter is the lesser studied, with entropy noise believed to be its main …

In future Ultra-High By-Pass Ratio turboengines, the turbomachinery noise (fan and turbine
stages mainly) is expected to increase significantly. A review of analytical models and …

This paper presents recent progress in the field of thermoacoustic combustion instabilities in
propulsion engines such as rockets or gas turbines. Combustion instabilities have been …

Thermoacoustic instability is a flow instability that arises due to a two-way coupling between
acoustic waves and unsteady heat release rate. It can cause damaging, large-amplitude …

Composition noise has recently received increasing attention for its potential to contribute
significantly to the indirect noise mechanism. In this study, the importance and definition of …

The propagation of acoustic, entropy and vorticity waves through turbine stages is of
significant interest in the field of core noise. In particular, entropy spots have been shown to …

A method to predict combustion noise in real aero-engines using Large Eddy Simulations
(LES) of the combustion chamber coupled with an analytical approach to model the acoustic …

This paper reviews both direct and indirect combustion noise. For convenience, they will
simply be referred to as combustion noise and entropy noise. Combustion noise has been …

Entropy noise corresponds to acoustic fluctuations generated inside gas-turbine engines
when temperature (entropy) spots are accelerated by the mean flow. This type of noise …

In gas turbines, flow fluctuations generated by the flame are accelerated through the turbine
and produce sound that may trigger combustion instabilities when propagating back to the …