Experimental investigation of an aeroacoustic feedback mechanism on a two-dimensional side mirror model
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- 作者：M.J. Werner ; m.werner@iag.uni-stuttgart.de" class="auth_mail" title="E-mail the corresponding author ; W. Wü ; rz ; E. Krä ; mer
- 关键词：Tonal self-noise ; Aeroacoustic feedback loop ; Side mirror
- 刊名：Journal of Sound and Vibration
- 出版年：2017
- 出版时间：20 January 2017
- 年：2017
- 卷：387
- 期：Complete
- 页码：79-95
- 全文大小：3499 K
文摘
The tonal self-noise emission of a two-dimensional blunt-body side mirror model is investigated experimentally in order to characterize the underlying source mechanism. The two-dimensional side mirror design is closely related to an automotive side mirror model1 which generates tonal self-noise. The examined flow field and tonal noise emission of the two-dimensional side mirror indicates the existence of an aeroacoustic feedback mechanism comprising convective boundary layer instability waves, their scattering to acoustic waves at the trailing edge and the acoustic receptivity at a dominant feedback point. Fundamental evidence of this concept is found in the typical variation of the discrete-frequency noise emission with the free-stream velocity as well as a laminar flow separation in the vicinity of the trailing edge featuring massively amplified discrete-frequency modes. The existence of an aeroacoustic feedback loop is finally confirmed by the systematic variation of the feedback loop resonance length, which is a crucial loop parameter.