Indirect noise generated by the acceleration of synthetic compositional and entropic
perturbations through non-isentropic nozzles is measured experimentally. A physics-based …

We investigate the low frequency transfer functions for acoustic and entropic perturbations
through nozzles and nozzle guide vanes. Previous theories rely on the isentropic …

1 t= time T= time period TO= time period a solenoid valve is open u= vector of actuation
signals of solenoid valves U= super-vector of actuation U∗= optimized super-vector of …

Acoustic liners have traditionally been used to reduce fan noise from the aircraft engine
intake. To increase noise reduction there are now plans to also put liners in hot stream parts …

Thermo-acoustic instabilities in gas turbine combustors can prevent the implementation of
modern combustion concepts, which are essential for higher efficiency and lower emissions …

N modern gas turbines achieve energy conversion efficiencies of approximately 40% by the
utilisation of various design methods and materials. However, the main part of the primary …

Pressure fluctuations in combustors arise either directly from the heat release rate
perturbations of the flame (direct noise), or indirectly from the acceleration of entropy …

An experimental facility was recently developed at the Georgia Tech Research Institute to
measure the acoustic scattering coefficients of a test article under mean flow, high …

Since the efficiency increase of state-of-the-art gas turbines has become incrementally
smaller, a significant improvement seems unlikely using the established concepts …

Combustion noise is increasing its relative contribution to aircraft noise, while other sources
are being reduced and new low-NOx emission combustion chambers being built. Two …