Two Dimensional Subsonic Wind Tunnel Tests on a 20 Percent Thick, 5 Percent Cambered Circulation Control Airfoil

Experimental and numerical results for the flow through a stator cascade with active flow control are discussed. By blowing air through a slot close to the trailing edge of the aerofoils, the deflection angle as well as the static pressure rise in the stator are increased. The aerofoil design is representative for a 1st-stage stator geometry of a multi-stage compressor adapted for low–speed applications. To allow a reasonable transfer of the high-speed results to low-speed wind tunnel conditions, a corresponding cascade geometry was generated applying the Prandtl–Glauert analogy. With this modified cascade numerical simulations and experiments have been conducted at a Reynolds number of 5 · 105. As a reference case two-dimensional flow simulations without circulation control are considered using a Navier–Stokes solver. In the related wind tunnel tests three–dimensional conditions occur in the test rig. Nevertheless five–hole probe measurements in the wake of the blade mid section show a good agreement with the theoretical characteristics. Additional investigation along the whole blade span gives a deeper insight into the flow topology. For design conditions different blowing rates are applied. The wind tunnel tests confirm the positive benefit, which is predicted by two-dimensional calculations. The offset between simulated and measured pressure rise decreases with increasing blowing mass flows due to the reduction of the axial velocity ratio. This result is related to a redistribution of the passage flow which can only be explained in a three–dimensional analysis including the side wall influence. The benefit of the circulation control at varying blowing rates is finally characterized by the efficiency and the static pressure rise per injected energy.

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Two-Dimensional Subsonic Wind Tunnel Evaluation of Two Related Cambered 15-Percent Thick Circulation Control Airfoils

10.21236/ada055140 ◽

1977 ◽

Cited By ~ 17

Author(s):

Jane Abramson

Keyword(s):

Wind Tunnel ◽

Circulation Control ◽

Two Dimensional ◽

Subsonic Wind Tunnel

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Wind Tunnel Test of a Blended Wing Aircraft in Ground Effect With Active Flow Control

Volume 1: Advances in Aerospace Technology ◽

10.1115/imece2016-65683 ◽

2016 ◽

Author(s):

Michael Mayo ◽

Jonathan Carroll ◽

Nicholas Motahari ◽

Warren Lee ◽

Robert Englar

Keyword(s):

Wind Tunnel ◽

Active Flow Control ◽

Wind Tunnel Test ◽

Ground Effect ◽

Circulation Control ◽

Wing Model ◽

Subsonic Wind Tunnel ◽

Test Methodology ◽

Tunnel Floor ◽

Lift And Drag

This paper describes the test methodology and results for a wind tunnel experiment featuring a blended wing aircraft in ground effect with built-in circulation control. A 82.55cm wingspan blended wing model was tested in a subsonic wind tunnel at velocities ranging from 18m/s – 49m/s and corresponding Reynolds numbers ranging from 130k – 350k. Pitch angle was held constant at 0 degrees and the height above the wind tunnel floor was modified to determine lift and drag modification due to ground effect. At a normalized height (y/bw) of 0.06, ground effect increased lift production by 24% and reduced drag by 22% when compared to a normalized height of 0.5. The addition of the circulation control significantly increased the lift production of the model at a cost of increased drag. At a normalized height of 0.031, the lift production increased by 200% at a blowing coefficient of 0.01, but the drag also increased by 72%, ultimately increasing L/D by 178%. Experimental results also suggest that ground effect and circulation control have a synergistic effect when used simultaneously. The effects of Reynolds number and circulation control slot height are also investigated.

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