Control of flow separation from a curved ramp using a steady-blowing jet

This work experimentally investigates flow separation control over a two-dimensional curved ramp using a spanwise steady-blowing slit jet. The flow separation and reattachment are first characterized in the absence of control for the momentum-thickness-based Reynolds number Re-? = 2000-15 000. Under control, the separation bubble sizes or pressure coefficient C-p,C-end at the end of the ramp exhibits a dependence on Reh, blowing jet angle a, and jet Reynolds number Re-d. It is found that, for a given a, the relationship C-p,C-end = f(1) (Re-?, a, Re-d) may be reduced to C-p,C-end = f(2)(C-m), where C-m = U-j/U-8 is the jet velocity ratio. That is, given the same C-m, C-p,C-end remains unchanged, irrespective of different Re(? )or Re-d. It is further found that flow separation from the ramp may be completely suppressed given a small a, i.e., a = 55 degrees, but not when a is large, i.e., >85 degrees. The corresponding mechanisms behind are discussed in detail.

Automated summary

This study experimentally investigates the control of flow separation over a two-dimensional curved ramp using a spanwise steady-blowing slit jet. The relationship between separation bubble sizes or pressure coefficient at the end of the ramp and jet velocity ratio is found. It is also discovered that flow separation from the ramp can be completely suppressed with a small jet angle, but not with a large jet angle.