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Connection Between Flow Structure and Separation Control for Various Fluidic Oscillator Spacings
The influence of actuator spacing on separation control using fluidic oscillators is experimentally investigated on a wall-mounted hump. Momentum inputs up to Cμ=2.5% are tested at four different spacings (Δz/c=2.27, 4.55, 6.82, and 9.09%), at Re=1.0⋅106 and M∞=0.09. For all spacings, the control au...
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Published in: | AIAA journal 2022-07, Vol.60 (7), p.4227-4239 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The influence of actuator spacing on separation control using fluidic oscillators is experimentally investigated on a wall-mounted hump. Momentum inputs up to Cμ=2.5% are tested at four different spacings (Δz/c=2.27, 4.55, 6.82, and 9.09%), at Re=1.0⋅106 and M∞=0.09. For all spacings, the control authority is characterized by two distinct regimes associated with boundary-layer control and circulation control. The two narrow spacings show steep control authority gradients in the transition between boundary-layer control and circulation control. The time-averaged flowfields from spanwise stereoscopic particle image velocimetry (PIV) vary significantly between the presented spacings, but the circulation normalized by mass flow rate per jet remains constant for a given momentum input in the boundary-layer control regime. When the spacing is too small for a given oscillator design, the introduced vorticity is unorganized and actuation is less effective for a given momentum input. Once the flow is attached, the circulation reduces for larger momentum inputs (circulation control). This indicates a connection between increased control authority and decreased circulation in the circulation control regime. These findings are supported by novel circulation metrics that describe the level of organization in the flowfield. |
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ISSN: | 0001-1452 1533-385X |
DOI: | 10.2514/1.J061334 |