Abstract
The characteristics of turbulent boundary layer over streamwise aligned drag reducing riblet surface under zero-pressure gradient are investigated using particle image velocimetry. The formation and distribution of large-scale coherent structures and their effect on momentum partition are analyzed using two-point correlation and probability density function. Compared with smooth surface, the streamwise riblets reduce the friction velocity and Reynolds stress in the turbulent boundary layer, indicating the drag reduction effect. Strong correlation has been found between the occurrence of hairpin vortices and the momentum distribution. The number and streamwise length scale of hairpin vortices decrease over streamwise riblet surface. The correlation between number of uniform momentum zones and Reynolds number remains the same as smooth surface.
| Original language | English |
|---|---|
| Pages (from-to) | 2433-2442 |
| Number of pages | 10 |
| Journal | Chinese Journal of Aeronautics |
| Volume | 32 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - 1 Nov 2019 |
Keywords
- Coherent structures
- Particle image velocimetry
- Riblet
- Riblet surface
- Turbulent boundary layer
- Uniform momentum zones