The unsteady response of nozzles with steady heat transfer forced by acoustic and/or
entropy waves is modelled. The approach is based on the quasi-one-dimensional linearised …

In this work, we investigate both numerically and theoretically the sound generated by
entropy waves passing through sudden area expansions. This is a canonical configuration …

An experimental cold-gas study of the response of a choked convergent–divergent nozzle to
swirl perturbations is presented. The perturbations were obtained by means of upstream …

Abstract A high-frequency (1.5 kHz) spontaneous Raman spectroscopy measurement
technique is developed and applied to measure external fluctuations generated in the local …

Entropy waves are generated in many technically relevant flow processes such as
combustion, mixing, or convective heat transfer. When accelerated, entropy waves generate …

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 …

We propose a mathematical model from physical principles to predict the sound generated
in nozzles with dissipation. The focus is on the sound generated from the acceleration of …

Thermoacoustic instabilities arise from the feedback between an acoustic field and the
unsteady heat released in a burner, yielding self-sustained oscillations. A fundamental …

Low emission aircraft engines burn in a lean regime, which makes the combustor
susceptible to unsteady combustion. Along with improper mixing and air cooling, the …

Indirect combustion noise, as an important source of noise in gas turbines, was traditionally
attributed solely to entropy waves. In recent years, compositional waves were introduced as …