Abstract
A flat plate separation flow with a diffusive upper wall was designed to simulate the boundary layer separation of a low pressure turbine cascade suction surface. Large eddy simulation with the dynamic Smagorinsky model was adopted to investigate flow dynamics and separation control effectiveness of a dimple under adverse pressure gradient on the flat plate. The effect of different ratio of leading edge boundary layer thickness to depth (R=0.378, 0.994, 1.453) on dimple flow dynamics and control effectiveness was investigated. The results show that the horseshoe vortex is the leading factor in the dimple flow dynamics for all three cases. Periodical shedding of the horseshoe vortex forms hairpin vortex lines arranged in dimple wake. The legs of the hairpin vortex are adjacent to the boundary layer and form streamwise vortex. In addition, the streamwise vortices absorb main stream high kinetic energy fluid into the boundary layer and augment the energy of the boundary layer. It appears that the horseshoe vortex and hairpin vortex lines are most effective to the suppression of boundary layer separation.
| Original language | English |
|---|---|
| Pages (from-to) | 27-32 |
| Number of pages | 6 |
| Journal | Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University |
| Volume | 44 |
| Issue number | 9 |
| State | Published - Sep 2010 |
Keywords
- Dimple
- Flow control
- Large eddy simulation
- Low pressure turbine
- Separation flow