Bionics - Natural but Innovative Methods Improve the Aeroacoustic Engineering

Abstract

This paper presents the aeroacoustics result of the trailing edge noise prepared wings two species of owl - Barn owl (Tyto alba), called “good hearing” and Northern hawk-owl (Surnia ulula), called “good seeing”. The acoustic performance comparisons between the Barn owl and Northern hawk-owl show that there are differences between the sound intensity the studied wings. These results prove that the special sound suppression characteristics of wing feather play an important role for their silent flight. Therefore the flat plates with the cutting trailing edge have been studied. At lower speeds, a better noise reduction effect was obtained for the plates with edges as elliptical arcs. On the basis of the above tests it can be concluded that other types of notches on the trailing edge (not just a sawtooth) also reduce the aerodynamic noise of flat plate.