Publication: Frequency Dependence on Core Dynamics in Multiple Vortex Interactions
All || By Area || By Year| Title | Frequency Dependence on Core Dynamics in Multiple Vortex Interactions | Authors/Editors* | Z. C. Zheng, Wenhua Li |
|---|---|
| Where published* | AIAA/CEAS Aeroacoustics Conference |
| How published* | Proceedings |
| Year* | 2007 |
| Volume | -1 |
| Number | -1 |
| Pages | |
| Publisher | |
| Keywords | |
| Link | |
| Abstract |
In a vortex system with multiple vortices such as a complicated aircraft vortex wake, the sound emission frequency of the unsteady vortex core is subjected to change because of interactions between multiple vortices. The behavior of the influence, indicated by the ratio between the core size and the distance of the vortices, and the underlining vortex core dynamic mechanisms are investigated. A vortex particle method is used to simulate the vortex core dynamics in two-dimensional, inviscid and incompressible flow. The flow field, in the form of vorticity, is employed as the source in the far-field acoustic calculation using a vortex sound formula. Cases of co-rotating vortices and a multiple-vortex system composed of two counter-rotating vortex pairs are studied for applications to aircraft wake vortex sound. The study shows, without vortex merging, individual frequencies can be clearly identified that are due each to core rotation (self induction) and co-rotating motion of a vortex center around the other (mutual induction). The ratio of the core size and the distance between vortices does not seem to significantly influence the frequency of vortex core rotation. With vortex merging, a single frequency due to the merged vortex core is generated. |
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