Some observations on the aerodynamics of an airfoil with a jet exhausting from the lower surface

Leopold, Devin R.; Krothapalli, A.; Tavella, Domingo

doi:10.2514/6.1983-173

Cited by 5 publications

(6 citation statements)

References 3 publications

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“…Although the validation does show that the computational methodology is able to capture the behavior of this type of flow, the momentum coefficients applied by Leopold et al . are well above (by an order of magnitude) the range considered in this study.…”

Section: Validationmentioning

confidence: 51%

“…Several studies were therefore made to compare OVERFLOW‐2 results with the results of experiments, including those conducted by Boeije et al . and Leopold et al . Both of these were 2‐D wind tunnel experiments on NACA 0018 airfoils with jets.…”

Section: Validationmentioning

confidence: 99%

“…To insure that the applied methodology is capable of capturing the complex flow physics and of predicting lift, comparisons were made with the wind tunnel test carried out by Leopold et al . In this wind tunnel test, a NACA 0018 airfoil with a chord length of c = 15 cm has a jet of width h jet = 0.1 cm placed at x/c = 0.5.…”

Section: Validationmentioning

confidence: 99%

“…The experimental values are taken from the paper by Leopold et al . . The bars around the computational results show the standard deviation of the oscillations in the predicted lift value.…”

Section: Validationmentioning

confidence: 99%

“…Tangential surface jets have also been used to provide circulation control by placing them near the trailing edge to cause changes in the Kutta condition through the Coanda effect and thereby change the aerodynamic properties of the airfoil . In other cases where the jets instead blow perpendicular to the airfoil, they are often used to disrupt the boundary layer, but may also provide flow improvements by re‐energizing the turbulent boundary layer . The two different concepts of flow separation control versus lift control are illustrated in Figure .…”

Section: Introductionmentioning

confidence: 99%

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Comparison of pneumatic jets and tabs for Active Aerodynamic Load Control

Blaylock¹,

Chow²,

Cooperman³

et al. 2013

Wind Energy

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A fast, efficient way to control loads on utility scale wind turbines is important for the growth of the wind industry. Microtabs and microjets are two Active Aerodynamic Load Control devices, which address this need. Both act perpendicular to the surface of the airfoil, and these actively controlled devices are used to mitigate changes in aerodynamic loading experienced by wind turbine rotors due to wind gusts, wind shear, or other atmospheric phenomena. This work explores the aerodynamic effects of microjets and then compares them to those of microtabs. Flow around an airfoil with an activated microjet at the trailing edge has been simulated using the Reynolds-averaged Navier-Stokes solver OVERFLOW-2. Using a Chimera overset grid topology, a microjet has been placed near the trailing edge of the lower surface of a NACA 0012 airfoil. For a jet velocity about half of the freestream velocity, the microjet can change the lift up to ΔC L = 0.2, but the amount of change varies with the momentum coefficient of the jet. The change in lift is not symmetric for positive and negative angles of attack due to changes in the boundary layer thickness with angle of attack. Increasing the Reynolds number reduces the effectiveness of the microjet only slightly. The effects of jet velocity, jet activation time, and airfoil angle of attack on airfoil lift, drag, and pitching moment are compared with previous work, which illustrates the deployment of a microtab at the 95% chord location of a NACA 0012 airfoil. This study shows that microjets and microtabs have very similar responses in lift and pitching moment, but the drag for the microjet is noticeably lower.

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Section: Validationmentioning

confidence: 51%

Section: Validationmentioning

confidence: 99%

Section: Validationmentioning

confidence: 99%

Section: Validationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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