Computational aeroacoustics in mechanical and aerospace engineering: Present status and problems to be solved
| Autor: | Kato, Chisachi |
|---|---|
| Jazyk: | japonština |
| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | 宇宙航空研究開発機構特別資料: 航空宇宙数値シミュレーション技術シンポジウム2003論文集 = JAXA Special Publication: Proceedings of Aerospace Numerical Simulation Symposium 2003. :29-34 |
| ISSN: | 1349-113X |
| Popis: | This paper summaries the present status and future directions of the methods in computational aeroacoustics. Emphases are placed on the practical applications of these methods in mechanical and aerospace engineering. After giving a brief introduction to computational aeroacoustics, this paper will first classify those methods proposed in this field and discuss the advantages and limitations associated with each of the methods. It will then present some of the examples for which each of the methods is applied. Finally, general direction of the computational aeroacoustics will be discussed together with those problems that need to be solved for making further progress in this field of research. All the methods in computational aeroacoustics can be classified into two categories: direct computation of sound and coupled methods of the acoustics source simulation and sound propagation calculations. Since aeroacoustics sound is very weak and propagating fluctuations in velocities, pressure and density of local fluid that are primarily generated due to the vortical motion of the source field, one can compute aeroacoustics sound by directly solving the unsteady compressible Navier-Stokes equations in the source and sound regions. This is called direct computation of sound. However, the direct computation of sound, particularly of sound generated from low Mach number flows, requires considerable computational resources and thus can only be applied to simple geometries and/or high speed flows. On the other hand, the coupled methods decompose the computations of source fluctuations and sound propagation based on an assumption that the propagating sound does not affect the source fluctuations. Extensive research that aims to apply this class of methods in mechanical and aerospace engineering has been made for the past decade and is still being made at present. It is now becoming tractable to compute aeroacoustics sound that is generated from relatively large-scale fluctuations in fluid flow, such as rotor-stator interaction and large separations from bluff bodies. One of the future directions in this field of research is computation of small-scale turbulence fluctuations such as the one in turbulent boundary layer and predictions of the resulting high-frequency sound. 資料番号: AA0047427006 レポート番号: JAXA-SP-03-002 |
| Databáze: | OpenAIRE |
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