Friction Drag Reduction on a Clark-Y Airfoil Using Uniform Blowing

Eto, Kaoruko; Kondo, Yusuke; Fukagata, Koji; Tokugawa, Naoko

doi:10.2514/6.2018-3374

Cited by 4 publications

(8 citation statements)

References 16 publications

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“…As shown in Fig. 2, the distributions of c p and c f in the present study are in reasonable agreement with those in the previous studies (Ihsan and Mustafa, 2016;Eto et al, 2019;Kondo, 2018). Table 1 shows the drag coefficient, C D , and the lift coefficient, C L , in the baseline case at two different Reynolds numbers.…”

Section: Validationsupporting

confidence: 93%

“…In order to validate the present code, some physical quantities are compared with those in the previous studies (Ihsan and Mustafa, 2016; Kondo, 2018;Eto et al, 2019) by using the pressure coefficient, c p , on the airfoil surface, the local skin friction coefficient, c f , on the upper surface in the baseline case, the drag coefficient, C D , and the lift coefficient, C L , in the baseline case at two different Reynolds numbers. The local pressure coefficient, c p , and the local skin friction coefficient, c f , are defined as…”

Section: Validationmentioning

confidence: 99%

“…In the combined control of UB and US cases, we apply the blowing and suction velocity of 0.14%U ∞ or 0.26%U ∞ , denoted as BS014 and BS026, respectively. Note that these magnitude for UB/US are decided from the previous experimental study (Eto et al, 2019). In the names of control cases, the character strings and numbers indicate the control conditions as summarized in Fig.…”

Section: Control Conditionsmentioning

confidence: 99%

“…Both of them show that the local skin friction is reduced by UB, and a combination of UB on the upper surface and US on the lower surface reduces the lift-to-drag ratio, which suggests that there is a possibility to improve the lift-to-drag ratio by optimizing the locations of UB and US sections. Recently, Eto et al (2019) investigated the control effect of UB in the flow around a Clark-Y airfoil experimentally. They realized UB at 0.14%U ∞ from a chamber covered by a porous metal surface and attained 20%-40% local friction drag reduction.…”

Section: Introductionmentioning

confidence: 99%

“…However, the proposed control designs based on these parametric studies have lacked the practical viewpoint because of the strong jet velocity or limitation in terms of the controlled surface area. Therefore, of particular interest in the present study is to focus on UB and US at a very weak amplitude (i.e., ∼ 0.1%U ∞ , similar to Kametani & Fukagata (2011) and Eto et al (2019)), which can be utilized as practical control methods against the mentioned controls above. The objective of this study is to seek for the optimum locations of UB and US for reduction of the friction drag and improvement of the lift-to-drag ratio of a Clark-Y airfoil, via a parametric study using RANS.…”

Section: Introductionmentioning

confidence: 99%

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Parametric study toward optimization of blowing and suction locations for improving lift-to-drag ratio on a Clark-Y airfoil

Ohashi

Morita

Hirokawa

et al. 2020

JFST

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Reynolds-averaged Navier-Stokes simulations (RANS) of flows around a Clark-Y airfoil with uniform blowing (UB) and uniform suction (US) are performed aiming at improvement of the airfoil performance. First, the control effect in the case with single UB or US applied on the airfoil surface is investigated at the various control locations. The magnitude of UB/US is 0.14% of the free-stream velocity, and the control region is set at four different locations on the upper and lower surfaces. The Reynolds number based on the chord length and the angle of attack are 1.5 × 10 6 and 0 • , respectively. It is found that the friction drag is decreased/increased by single UB/US control. It is also found that UB on the lower surface or US on the upper surface improves the lift-to-drag ratio, while UB on the upper surface or US on the lower surface worsens it. In the combined control of UB and US having the equal flow rate, the magnitude of blowing and suction is set at 0.14% or 0.26% of the free-stream velocity. The locations of blowing/suction and flow conditions are the same as those in the cases with either UB or US only. The simulation result suggests that the lift-to-drag ratio is improved by the combined control of UB on the lower surface and US on the upper surface. In particular, the lift-to-drag ratio is most improved by a combination of UB on the lower rear surface and US on the upper rear surface. In contrast, a combined control of UB on the upper front surface and US on the lower rear surface is identified as the most effective case for the friction drag reduction only.

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Section: Validationsupporting

confidence: 93%

Section: Validationmentioning

confidence: 99%

Section: Control Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Parametric study toward optimization of blowing and suction locations for improving lift-to-drag ratio on a Clark-Y airfoil

Ohashi

Morita

Hirokawa

et al. 2020

JFST

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Effects of the Actuation on the Boundary Layer of an Airfoil at Reynolds Number Re = 60000

Rodríguez

Lehmkuhl

Borrell

2020

Flow Turbulence Combust

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Experimental investigation on friction drag reduction on an airfoil by passive blowing

Hirokawa¹,

Eto²,

Fukagata³

et al. 2020

JFST

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Friction drag reduction effect of a passive blowing on a Clark-Y airfoil is investigated. Uniform blowing, conducted in a wall-normal direction on a relatively wide surface, is generally known as an active control method for reduction of turbulent skin friction drag. In the present study, uniform blowing is passively driven by the pressure difference on a wing surface between suction and blowing regions. The suction and the blowing regions are respectively set around the leading edge and the rear part of the upper surface of the Clark-Y airfoil in order to ensure a sufficient pressure difference for passive blowing. The Reynolds number based on the chord length is 0.65×10 6 and 1.55×10 6. The angle of attack is set to 0 • and 6 •. The mean streamwise velocity profiles on the blowing region and the downstream, measured by a traversed hot-wire anemometry, are observed to shift away from the wall by passive blowing. This behavior qualitatively suggests reduction of local skin friction on the wing surface. A quantitative assessment of the friction drag is performed using the law of the wall accounting for pressure gradients (Nickels, 2004), coupled with a modified Stevenson's law (Vigdorovich, 2016) to account for the weak blowing. From this assessment, the local friction drag reduction effect of passive blowing is estimated to reach 4% − 23%.

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Friction Drag Reduction on a Clark-Y Airfoil Using Uniform Blowing

Cited by 4 publications

References 16 publications

Parametric study toward optimization of blowing and suction locations for improving lift-to-drag ratio on a Clark-Y airfoil

Parametric study toward optimization of blowing and suction locations for improving lift-to-drag ratio on a Clark-Y airfoil

Effects of the Actuation on the Boundary Layer of an Airfoil at Reynolds Number Re = 60000

Experimental investigation on friction drag reduction on an airfoil by passive blowing

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