Séminaire des Doctorant·e·s :

Le 25 février 2010 à 17h30 - Salle 331

Présentée par Kulkarni Rahul - UM2

Stability of a thermoacoustic system: the role of linearity and non-linearity

Though, the thermoacoustic instabilities are known for a long time, they are still not fully understood. They result from the coupling between the acoustic waves and the flame and may lead to very large amplitude fluctuations in all the flow quantities. Traditionally, the framework of the classical linear stability analysis is followed for the instability study. The short time growth in the acoustic energy was not taken into the account. This transient growth can potentially trigger the non-linearity in the system. A controller designed based on the individual eigenmodes fail in this particular case. However, this linear analysis does not deny the importance of the non-linearity of in the system. The practical thermoacoustic systems are non-linear in nature. A FDF (flame describing function) based approached is followed to demonstrate the limit cycle prediction in a 1-D configuration.