Contribution
Lecture cancelled: On the Propagation of Incident Acoustic Waves through the Boundary Layer of a Large-Scale Cockpit-Fuselage Model
* Presenting author
Abstract:
A significant contribution to cabin noise comes from the engine’s acoustic emissions towards the fuselage. Depending on its position relative to the fuselage, the engine’s sound field will experience refraction, reflection and attenuation when propagating through the turbulent boundary layer developing on the fuselage’s skin. In the DLR project INTONATE, wind tunnel measurements were carried out on a 6.6 m long fuselage model of a short and medium-range aircraft with 1 m diameter in the DNW-NWB in Braunschweig to quantify the effect of the boundary layer on the propagation of an incident acoustic wave as a function of incidence angle, flight speed and boundary layer thickness. The aim of the investigation is to provide a database for the validation of numerical simulation codes, with respect to the propagation of broadband turboprop fan noise towards the fuselage, and cabin, of an aircraft.In the experiment, a laser-based impulsive point-like sound source is used to generate omni-directional sound waves, non-intrusively, at specific distances away from the fuselage and for variations in streamwise position. The acoustic pressure reaching the fuselage surface is acquired using surface-mounted flat sensor instrumentation. A comparison between the experimental and computational aeroacoustics simulations will be presented.