Conference_programme: 2.1 - Aeroacoustics

Lecture: Understanding the noise generated by a jet engine: a study of the 3D diffraction by a quarter-plane

Author(s): Moschou Marianthi, Assier Raphael , Parnell William

Summary:
Living or working near an airport can be quite annoying. One of the reasons is the noise generated by aeroengines. Hence, the understanding of noise generated by a jet engine, which is linked with the theory of diffraction of acoustic waves, is of great importance.\nCanonical diffraction theory investigates the diffraction of an incoming wave by an obstacle with simple geometry, but with certain characteristics, such as edges or corners. Most of the analytical methods in aeroacoustics are based on blade-gust interactions, where the blade is often modelled as a half-plane. The corresponding canonical problem is the Sommerfeld problem. Our goal is to understand the effect being caused by blade tips; hence we first need to study the three-dimensional diffraction by a quarter-plane, one of the last unsolved canonical problems in diffraction theory. \nA lot of progress has recently been made about the quarter-plane problem with simple boundary conditions, the widely known Dirichlet and Neumann boundary conditions thanks to the method of embedding formulae. This is a new technique used in diffraction theory that enables to fully describe the far-field in a scattering problem.\nIn this talk, we will focus on extending this method to more realistic boundary conditions of impedance type.\n

Corresponding author

Name: Ms Marianthi Moschou

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Country: United Kingdom