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Flow Structure on Nonslender Delta Wing: Reynolds Number Dependence and Flow Control

2016-03-01
Zharfa, Mohammadreza
Ozturk, Ilhan
Yavuz, Mehmet Metin
The flow structure over a 35 deg swept delta wing is characterized in a low-speed wind tunnel using techniques of laser-illuminated smoke visualization, laser Doppler anemometry, and surface-pressure measurements. The effects of Reynolds numbers and attack angles on the evaluation of flow patterns are addressed within the broad range of Reynolds number 10(4) < Re < 10(5) and attack angle 3 deg < alpha < 10 deg. In addition, the effect of steady blowing through the leading edges of the wing on flow structure is studied to delay three-dimensional surface separation. A comparison of two different blowing patterns, uniform blowing and decreasing blowing, is used to identify the effective regions on leading edges considering the ultimate influence of flow control. The results indicate that the effect of Reynolds number on flow structure is limited, such that beyond a certain Reynolds number, the flow structure demonstrates minimal variations with further increase in Reynolds number. Considering the results of the flow-control study, steady blowing through leading edge significantly alters the flow structure, and is quite effective in the eradication of three-dimensional surface separation. The decreasing-blowing pattern compared to uniform blowing seems to be more efficient on the overall flow structure, indicating that control through leading edge near the apex region is more effective.