Experimental study on aerodynamic sound generated from flow around a forward facing step

Autor: Yoshihiro SHIRASU, Yasumasa SUZUKI, Chisachi KATO
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Journal of Fluid Science and Technology, Vol 18, Iss 1, Pp JFST0020-JFST0020 (2023)
Druh dokumentu: article
ISSN: 1880-5558
DOI: 10.1299/jfst.2023jfst0020
Popis: Aerodynamic noise in high frequency band related in the flows around A-pillar is easily propagated to the cabin of the automobile. Understanding of the characteristics of the aerodynamic noise is needed to reduce the cabin noise. Moreover, understanding of the separated shear layer which is strongly affected by the condition of the step hight H to the boundary layer thickness δ is needed. In this study, far field sound and correlation measurement of flow velocity are measured to investigate the characteristics of aerodynamic noise and the relationship between H/δ and turbulence length scale L as eddy scale for the forward facing step. As a result, multiple gradual peaks in more than 1 kHz are observed in the aerodynamic sound spectra. Furthermore, it is found that turbulence length scale L increases for increasing of H/δ and turbulence length scale to step height for H/δ = 2.0 is almost equal to that for H/δ = 3.0. Then, it is clear that spectral peaks are strongly affected by step height. And it is confirmed that H/δ = 2.0 and 3.0 are equal in turbulence length scale to the step height.
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