Phased acoustic array measurements of a 5.75% hybrid wing body aircraft

Abstract

Detailed acoustic measurements of the noise from the leading-edge Krueger flap of a 5.75% hybrid wing body aircraft model were acquired with a traversing phased microphone array in the Arnold Engineering Development Complex NFAC 40-by 80-foot wind tunnel. The spatial resolution of the array was sufficient to distinguish between individual support brackets over the full-scale frequency range of 100 to 2875 Hz. For conditions representative of landing and takeoff configuration, the noise from the brackets dominated other sources near the leading edge. Inclusion of flight-like brackets for select conditions highlights the importance of including the correct number of leading-edge high-lift device brackets with sufficient scale and fidelity. These measurements support the development of a Krueger noise model which includes cove and bracket noise.

Evaluation of the noise impact of flap-tip fences installed on laminar wings

“…It is known that at off-design conditions, i.e., takeoff/climb and approach/landing phases, the performance of the laminar flow technology shows some critical aerodynamic issues and noise emission becomes very important. This is due, for instance, to the use of Krueger Flaps that, as illustrated by the studies of Moens and Capbern [3], are recognized as the most promising leading-edge device for laminar flow wing designs, but, when deployed, could have a negative impact on the overall aircraft performances and be responsible for tonal noise emission [4]. Another aspect which affects not only the extent of the laminar flow on the wing but also the acoustic performance of the aircraft is the location and the installation of the engines [5].…”

S1MAWind Tunnel New Aeroacoustic Capability: a Traversing Microphone Array

“…Traversing array acquisitions are also used in closed test section facilities such in the Arnold Engineering Development Complex (AEDC) at NASA Ames. Its very large dimensions offer a good opportunity to test different traversing arrays ( [10,11]). In most of the previous studies acoustic arrays are employed at discrete specific positions.…”