|
|
|
Article
Transition delay by means of base flow modulations
| Authors: |
Sattarzadeh, S. S., Shahinfar, S., Fallenius, B. E. G. , Fransson, J. H. M., Talamelli, A. |
| Document Type: |
Conference |
| Pubstate: |
Published |
| Journal: |
Bulletin of the American Physical Society, 64th Annual Meeting of the APS Division of Fluid Dynamics, Baltimore, November 20-22 2011 |
| Volume: |
|
| Year: |
2011 |
AbstractRecent experimental investigations have shown that spanwise modula- tions of the base flow may delay transition to turbulence2. In this study we explore the possibility to generate streaks of much larger amplitude than previously reported by using a row of miniature vortex generators (MVGs). Here, we present the rst boundary layer experiment where streak amplitudes exceeding 30% have been produced without having any secondary instability acting on them. Furthermore, the induced skin-friction drag due to the streaky base flow is quanti ed and it is demonstrated that the streaks can be reinforced by placing a second array of MVGs downstream of the rst one. In this way it is possi- ble to make the control more persistent in the downstream direction. We conclude that the specially designed set of MVGs, as a boundary layer modulator, is a promising candidate for successfully setting up robust and persistent streamwise streaks, which is a prerequisite for a successful flow control. This work is carried out within the AFRODITE programme funded by ERC.
|
|
