An evolutional process of three dimensional disturbances in laminar boundary layers
Abstract
As for the turbulent flow transition of boundary layer starting from the growth of a T-S (Tollmien-Schlichting) wave, the three dimensional wave configuration caused from the development of peak valley structure is one of the most important models. The turbulent flow transition of planar Poiseuille flow were investigated. As the results of experiments, the most probable cause of three dimensional wave formation were concluded to come from the distortion of main flow in the span direction. The synchronous three dimensional wave (a pair of oblique waves) is generated from the nonlinear interference of a two dimensional T-S wave with the three dimensional distortion part of the main flow. As the amplitude of the T-S wave increased over the threshold value of one percent, a synchronous three dimensional wave is predicted to develop from the two dimensional instability model. Experimental results were as follows: (1) the two dimensional T-S wave and three dimensional distortion of mean flow were given as the initial disturbance to Poiseuille flow and the timely development of the disturbance was numerically simulated using the Fourier Chebyshev spectrum method; and (2) as the amplitude of the T-S wave increased over the threshold value of one percent, the amplified three dimensional wave emerged. The amplification of the peak valley wave was confirmed to be caused from distortion of the main flow.
- Publication:
-
Proceedings of the 5th and 6th Seminars on Investigation and Control of Boundary-Layer Transition
- Pub Date:
- October 1990
- Bibcode:
- 1990sicb.proc...11A
- Keywords:
-
- Boundary Layer Transition;
- Computational Fluid Dynamics;
- Computerized Simulation;
- Flow Distortion;
- Three Dimensional Boundary Layer;
- Tollmien-Schlichting Waves;
- Wave Generation;
- Chebyshev Approximation;
- Fourier Series;
- Laminar Flow;
- Spectral Methods;
- Transition Flow;
- Transonic Flow;
- Turbulent Flow;
- Fluid Mechanics and Heat Transfer