Aeroacoustics is the study of sound within a moving flow.
With increasingly strict noise requirements on aircraft, understanding
the noise produced by aircraft and aircraft engines remains a concern in
the design of modern aircraft. Aircraft engine nacelles contain
acoustic linings designed to dampen the sound from the engine, but
unfortunately the models of acoustic linings are lacking and not well
understood. Even simplified laboratory experiments to investigate the
performance of acoustic linings often disagree about the properties of
the acoustic linings under investigation.
In this talk, I will try to explain how sound in aircraft engines is
currently modelled, what the problems are with this model, and the
various attempts that have been made at correcting these problems. I
will also show just how far we’ve still got to go to get theory and
experiment to agree.