This paper examines the sound generated by an inviscid low Mach number vortex filament as it moves near a semi-infinite splitter in a two-dimensional duct with and without vortex shedding at the splitter edge. A strong one-dimensional sound is produced when the vortex is close to the edge. Without vortex shedding, the sound is shown to consist of predominantly compressive pulses which propagate in the split duct section and a rarefaction pulse downstream of the splitter edge, regardless of the position of the half plate and the direction of vortex motion. The vortex shedding results in no horizontal force at and no sound going downstream of the edge. Results also suggest that the vortex shedding does not always result in noise reduction. In all cases with and without vortex shedding, the narrower section of the split duct experiences the most sound in general. The surprising result is found that the confinement of the edge-scattering flow within a duct does not much affect the high acoustic efficiency of the scattering process.
Tang, S. K. (2022). Duct sound produced by vortex flow over a splitter plate. Journal of Sound and Vibration, 541, Article 117352. https://doi.org/10.1016/j.jsv.2022.117352