We are now at a point where airframes, aeroengines and their integration require radical
changes to meet increasingly aggressive environmental targets. Generally, fan noise …

An explicit solution is given of a pulse reflecting in time domain at a Helmholtz resonator
impedance wall that provides some insight into the reflection problem in time domain and at …

The Ingard–Myers condition, modelling the effect of an impedance wall under a mean flow
by assuming a vanishingly thin boundary layer, is known to lead to an ill-posed problem in …

The walls of ducts containing flow are often acoustically lined in order to reduce sound.
Many simple models of acoustic linings assume the lining to be linear and locally reacting; …

In a duct of constant cross section, with a medium and boundary conditions independent of
the axial position, the wave equation for time-harmonic perturbations may be solved by …

This thesis proposes a set of theoretical models to predict, during the conceptual design
phase, the sound emitted by the fan stage of an aero-engine, which is due to the interaction …

This paper presents a method for detecting small blockages (ie, blockages whose radial
length scale LR is significantly smaller than the pipe diameter D) in water supply lines. A …

This paper presents a method for identifying a cluster of small blockages (ie, blockages with
length on the order of centimeters and radial extent on the order of millimeters and …

Fan broadband noise is a major component of the total noise emitted by turbofan engines,
especially at lower shaft speeds. It is generated in the rotor/stator region, but the exact origin …

Acoustics within mean flows are governed by the linearized Euler equations, which possess
a singularity wherever the local mean flow velocity is equal to the phase speed of the …