On Improving CLEAN-SC Maps in the Wind Tunnel

2024-01-2936

06/12/2024

Event
13th International Styrian Noise, Vibration & Harshness Congress: The European Automotive Noise Conference
Authors Abstract
Content
When traveling in an open-jet wind tunnel, the path of an acoustic wave is affected by the flow causing a shift of source positions in acoustical maps of phased arrays outside the flow. The well-known approach of Amiet attempts to correct for this effect by computing travel times between microphones and map points based on the assumption that the boundary layer of the flow, the so-called shear layer, is infinitely thin and refracts the acoustical ray in a conceptually analogy to optics. However, in reality, the turbulent nature of both the not-so-thin shear layer and the acoustic emission process itself causes an additional smearing of sources in acoustic maps, which in turn causes deconvolution methods based on these maps – the most prominent example being CLEAN-SC – to produce certain ring effects, so-called halos, around sources. In this paper, we intend to cast some light on this effect by describing our path of analyzing/circumventing these halos and how they are linked to the CLEAN algorithm itself. Moreover, we outline a methodological extension to CLEAN-SC, which comes at a reasonable computational cost but effectively eliminates this effect in real-world measurements.
Meta TagsDetails
DOI
https://doi.org/10.4271/2024-01-2936
Pages
8
Citation
Puhle, C., Meyer, A., and Döbler, D., "On Improving CLEAN-SC Maps in the Wind Tunnel," SAE Technical Paper 2024-01-2936, 2024, https://doi.org/10.4271/2024-01-2936.
Additional Details
Publisher
Published
Jun 12
Product Code
2024-01-2936
Content Type
Technical Paper
Language
English