Search

Your search keyword '"Tollmien–Schlichting wave"' showing total 3 results
Start Over Descriptor "Tollmien–Schlichting wave" Language japanese
3 results on '"Tollmien–Schlichting wave"'

1. Effects of inclination of protuberance on sound radiation from a protuberance in a laminar boundary layer

Author

Masashi KOBAYASHI and Masahito ASAI

Subjects
boundary layer, tonal sound, instability, tollmien-schlichting wave, protuberance, Mechanical engineering and machinery, TJ1-1570, Engineering machinery, tools, and implements, TA213-215
Abstract

When a two-dimensional protuberance whose height was as high as the boundary-layer thickness was glued on the boundary-layer plate, tonal sound was radiated by a feedback-loop mechanism between protuberance-generated sound and Tollmien-Schlichting (T-S) wave generated by the leading-edge receptivity to the upstream-propagating sound. In the present study, effects of inclination of protuberance on sound radiation are investigated experimentally at low Mach numbers. The results showed that generation of tonal sound was very sensitive to the inclination angle of protuberance and the sound pressure level rapidly decreased with the inclination angle. When the inclination angle exceeded only 10°, tonal sound almost disappeared. Flow visualization of the associated disturbance development near the protuberance also supported that the feedback mechanism was significantly weakened when the protuberance was only slightly inclined to the main stream.

Published
2015
Full Text
View/download PDF

2. 圧縮性境界層の遷移機構の研究

Author

Maekawa, Hiroshi and Watanabe, Daisuke

Subjects
3次元境界層, 線形安定性解析, Tollmien-Schlichting wave, 流れの遷移, linear stability analysis, ヘアピン渦, 圧縮性境界層, 直接数値シミュレーション, hairpin vortex, compressible boundary layer, Reynolds number, Physics::Fluid Dynamics, Tollmien-Schlichting波, direct numerical simulation, flow visualization, レイノルズ数, flow transition, 流れの可視化, three dimensional boundary layer
Abstract

Spatial direct numerical simulations are performed to study the formation and development of three-dimensional structures in a compressible flat plate boundary layer, where the free-stream Mach number is 0.5 and the Reynolds number at the inlet based on the displacement thickness 1,000. A pair of neutral/stable oblique modes and a TS wave is superimposed on the laminar profile at the inlet plane of the boundary layer computational box. The magnitudes of the disturbances are chosen to be 1 percent or 0.5 percent of the free-stream value. After saturation of the T-S wave, the oblique modes produce peak-valley splitting downstream and hairpin vortices (hairpin packet) on the low speed streak are observed further downstream. So-called sub-harmonic transition appears downstream in the boundary layer. The numerical results show that the details of three-dimensional structure depend on the magnitude of the disturbance., 資料番号: AA0049208003, レポート番号: JAXA-SP-05-012

Published
2006

3. Two-dimensional bifurcation structure in Poiseuille flow

Author

Umeki, Makoto

Subjects
流体力学的カオス, chaos, 直接数値シミュレーション, 分岐構造, 擬スペクトル法, Poiseuille flow, bifurcation structure, transition route, turbulent flow vorticity distribution, 渦度変動相関, fluid dynamic chaos, Hopf bifurcation, 遷移道筋, transition to turbulence, Tollmien-Schlichting wave, turbulence spatial structure, 乱雑化開始, pseudospectral method, randomization onset, 乱流空間構造, カオス, 乱流渦度分布, direct numerical simulation, トルミーン・シュリヒティング波, 乱流遷移, vorticity fluctuation correlaton, ポアズイユ流れ, Hopf分岐
Abstract

航空宇宙技術研究所 28-29 Sep. 1992. 25-26 Apr.1993 東京 日本, National Aerospace Laboratory 28-29 Sep. 1992. 25-26 Apr.1993 Tokyo Japan, フーリエ・チェビシェフ擬スペクトル法を用いた直接数値シミュレーションにより2次元ポアズイユ流れにおける分岐と乱流遷移とを調べた。α=1、5450＜Re＜6150の場合に定常進行波にHopf分岐が現れることが示された。空間構造と乱流特性につき検討した。, Bifurcations and transitions to turbulence in two dimensional Poiseuille flow are studied by direct numerical simulation based on the Fourier-Chebyshev pseudospectral method. It is shown that two successive Hopf bifurcations appear on the steady progressive wave when alpha = 1 and 5450 less than Re less than 6150. Spacial structures and turbulent characteristics are examined., 資料番号: AA0004170012, レポート番号: NAL SP-21

Published
1993

Catalog

Books, media, physical & digital resources
See catalog results