Date & Time: Thursday, 4th Mar, 2010 16:00-17:00.
Venue: Ramanujan Hall, Mathematics Department
Title: Nonlinear acoustical guided waves
Speaker: Dr. Francois Coulouvrat, University of Paris
Abstract: Noise reduction is an important issue for aircraft industry. This work investigates the fundamental of so-called « Buzz-saw Noise » (BSN) due to shock waves emanating from the tip of engine fan blades when rotating at supersonic speeds. Based on a linear modal expansion with varying amplitudes, we show how to reduce a nonlinear partial differential equation to a system of ordinary differential equations. This quasi modal model will then be illustrated to two simple geometries : a 2D one and a 3D one. The 2D geometry will help illustrate the notion of dispersive or non dispersive interations. The 3D case will explain the observed characteristics of BSN.