Effect of Re-Number, Ma-Number and Angle of Attack on Slat Noise Based on a Test Vortex Injected Upstream of the SLAT-Hook

Abstract

The noise sources of commercial aircrafts may be split in two categories: the first category covers all the noise generated by the propulsion unit while the second category is associated with the airframe itself. Based on the development of high-bypass low noise turbofan engines the contribution of airframe noise in approach and landing configuration is enhanced, thus playing a growing role in aircraft design. The high-lift devices, especially the upper slat trailing edge portion and the flap sidewalls as well as the landing gear are the main contributors to the airframe noise during take-off and landing. This paper presents the results of a Computational Aeroacoustics (CAA) analysis for a 2D high-lift profile as part of the Airbus strategy for low-noise high-lift design. Previous, primarily experimental [1,2,3], research activities have shown that the slat (also in conjunction with the main wing leading edge) is one of the major contributors to high-lift airframe noise. With focus on the slat, especially the pressure side (cove area) and the upper trailing edge are to be identified as being the primary source of slat noise. Thus, the current activities concentrate on investigating slat noise by injecting a single test-vortex upstream of the slat hook (i.e. the lower slat trailing edge) for different Re-numbers, Ma-numbers and angles of attack into a steady state flow field coming from CFD.