Vortex Flow Structure Generated by an Inclined Sweeping Jet in Cross Flow

A sweeping jet from the fluidic oscillator has attracted attention as an active flow control device in recent years. However, the flow field generated by the sweeping jet ejected into a main flow is not only the complex behaviors of the sweeping jet but also the interaction between the sweeping jet and the main flow, it is easy to consider that it will be a very complex phenomenon. However, the detailed of the vortex structure has not understood sufficiently. Three dimensional vortex structure generated by the interaction between the sweeping jet and the main flow quantitatively was investigated by the stereo PIV measurement. For Vj/V∞ = 6.0, the interaction between the sweeping jet and the main flow is not very large, and the decay of the sweeping jet causes the decay of the entire vortex structure. However, for Vj/V∞ = 2.0, the sweeping jet and the main flow strongly interact, and form a vortex flow with a main rotation component in the direction perpendicular to the main flow, instead of a linear flow in the main flow direction. From the viewpoint of separation control, the vortex structure generated for Vj/V∞ = 2.0 may be extremely effective for separation control since the sweeping jet strongly interacts with the main flow, and not only induces a vortex flow perpendicular to the main flow, but also maintains this structure continuously down the wake.