1. Characteristic features of a wave packet in rotating-disk flow
- Author
-
Nishizawa, Akira and Takagi, Shohei
- Subjects
wave packet ,linear stability theory ,波数 ,absolute instability ,3 dimensional flow ,boundary layer ,境界層 ,research and development ,Reynolds number ,3次元流 ,hot-wire sensor ,C-F mode ,波束 ,熱線センサ ,回転円盤流 ,絶対不安定性 ,rotating disk flow ,線形安定性理論 ,対流 ,wave number ,convection ,C-Fモード ,研究開発 ,Reynolds数 - Abstract
Characteristic features of a wave packet in a rotating-disk boundary layer were experimentally investigated. The point disturbance originating from a small hole on the disk forms an isolated wave packet which consists of two types of unstable waves. Comparison with the prediction by Itoh's linear stability theory enabled the identification of these waves; the streamline-curvature (S-C) modes with the smaller wave number in the circumferential direction and the higher frequency are observed prior to the appearance of cross-flow (C-F) modes with the larger wave number and lower frequency. The hot-wire analyses quantitatively show that such characteristic features of these modes are in good agreement with the theoretical results. Time trace of the edge of packet does not indicate the occurrence of absolute instability but shows that the wave packet convectively passes through the radius line corresponding to the critical Reynolds number for the absolute instability predicted by Lingwood., 資料番号: AA0045947029, レポート番号: NAL SP-56
- Published
- 2002