Experimental investigation on noise emissions of an airfoil with non-flat plate trailing edge serrations

This paper presents an experimental study on the aeroacoustic characteristics of a NACA 0018 with nonflat plate-type serrated trailing edge at Reynolds numbers of 500000 in an open-jet wind tunnel. The experimental results show that noise reduction can be achieved in the moderate frequency range for nonflat plate type triangular serrated trailing edges, but at the cost of producing narrowband tone noise. The level of the vortex shedding noise declines when serration length 2 h decreases. It is imperative that the vortex shedding tone noise be completely suppressed when a novel slanting root serrated trailing edge is adopted. Meanwhile, the ability of broadband noise reduction is maintained.