This paper deals with experimental investigation of the lined wall boundary condition in flow
duct applications such as aircraft engine systems or automobile mufflers. A first experiment …

INCREASED understanding of acoustic liner effects on sound propagation through aircraft
engine nacelles is required for more efficient liner design. Numerous aeroacoustic duct …

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; …

Impedance eduction of acoustic liners with flow is commonly performed under the
assumption of a uniform velocity profile. In practice, the flow profile is not uniform and a …

The development of the advanced liner technology for aeroengine noise control
necessitates the impedance measurement method under realistic flow conditions. Currently …

In principle, the impedance of a locally reacting acoustic liner should be independent of the
structure of the sound field above the liner. Some experimental studies, however, have …

I. Introduction ccurately predicting the impedance of a given Single-degree-of-freedom
(SDOF) perforated liner in the presence of grazing flow is essential to designing the optimum …

Impedance eduction experiments on acoustic liners with flow have systematically shown the
educed impedance depending on the direction of the incident wave. Recent attempts to …

The acoustical behavior and the flow in a rectangular lined channel with grazing flow have
been investigated. The liner consists of a ceramic structure of parallel square channels and …

In aeroacoustic engineering, precise measurements of liner impedance with grazing flow
are crucial for optimizing noise reduction strategies. This paper introduces a novel 3D …