Computational and Experimental Analysis of a High-Performance Airfoil Under Low-Reynolds-Number Flow Condition

Anyoji, Masayuki; Nonomura, Taku; Aono, Hikaru; Oyama, Akira; Fujii, Kozo; Nagai, Hiroki; Asai, Keisuke

doi:10.2514/1.c032553

Cited by 79 publications

(45 citation statements)

References 15 publications

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“…The plateau pressure distribution is often reported in many LSB studies. 23,[27][28][29] In these cases, the plateau pressure distribution is observed in the steady region …”

Section: B Pressure and Skin Friction Distributionsmentioning

confidence: 94%

“…As a result, the separated shear layer reattaches to the surface as a turbulent state, which results in the rapid recovery of the surface pressure distribution. 19,21,22 In particular, the plateau pressure distribution has often been thought as a general feature of the LSB, 1-4 and thus in many prior studies, 18,19,[21][22][23][24][25][26][27][28][29] the formation of the LSB has been judged by the appearance of the plateau pressure distribution. With respect to the relation between the pressure distribution and the LSB characteristics, Anyoji et al 30 have experimentally measured surface pressure distributions of a 5% thickness blunt flat plate using pressure-sensitive paint (PSP) technique at the plate length based Reynolds numbers of Re c = 4.9 × 10 3 , 6.1 × 10 3 , 1.1 × 10 4 , 2.0 × 10 4 , and 4.1 × 10 4 .…”

Section: Introductionmentioning

confidence: 99%

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Mechanisms of surface pressure distribution within a laminar separation bubble at different Reynolds numbers

et al. 2015

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Mechanisms behind the pressure distribution and skin friction within a laminar separation bubble (LSB) are investigated by large-eddy simulations around a 5% thickness blunt flat plate at the chord length based Reynolds number 5.0 × 103, 6.1 × 103, 1.1 × 104, and 2.0 × 104. The characteristics inside the LSB change with the Reynolds number; a steady laminar separation bubble (LSB_S) at the Reynolds number 5.0 × 103 and 6.1 × 103, and a steady-fluctuating laminar separation bubble (LSB_SF) at the Reynolds number 1.1 × 104, and 2.0 × 104. Different characteristics of pressure and skin friction distributions are observed by increasing the Reynolds number, such that a gradual monotonous pressure recovery in the LSB_S and a plateau pressure distribution followed by a rapid pressure recovery region in the LSB_SF. The reasons behind the different characteristics of pressure distributions at different Reynolds numbers are discussed by deriving the Reynolds averaged pressure gradient equation. It is confirmed that the viscous stress distributions near the surface play an important role in determining the formation of different pressure distributions. Depending on the Reynolds numbers, the viscous stress distributions near the surface are affected by the development of a separated laminar shear layer or the Reynolds shear stress. In addition, we show that the same analyses can be applied to the flows around a NACA0012 airfoil.

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“…The plateau pressure distribution is often reported in many LSB studies. 23,[27][28][29] In these cases, the plateau pressure distribution is observed in the steady region …”

Section: B Pressure and Skin Friction Distributionsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Mechanisms of surface pressure distribution within a laminar separation bubble at different Reynolds numbers

et al. 2015

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“…Consequently, effects of specific heat ratio on aerodynamic characteristics are not large and become smaller as Mach number increases. Anyoji et al [33] numerically investigated the flowfield and the aerodynamic performance of the NACA 0012 at Re 23; 000 and M 0.20. Their results showed that the spanwise vortices break up near the transition point at α 9 deg.…”

Section: Effect Of Specific Heat Ratiomentioning

confidence: 99%

Effects of Mach Number and Specific Heat Ratio on Low-Reynolds-Number Airfoil Flows

et al. 2015

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The effects of Reynolds number, Mach number, and gas species (air and CO 2 ) on aerodynamic characteristics of a thin flat plate and a NACA 0012-34 airfoil were investigated under low-Reynolds-number (Re 0:43 × 10 4 to 4.1 × 10 4 ) and high-subsonic-flow (M 0.1 to 0.6) conditions. In addition to lift and drag measurements by a twocomponent balance system, the pressure-sensitive paint technique was applied to measure pressure profiles on the model surface. For the flat plate, the Reynolds number moderately affects the lift and drag characteristics because of a simple behavior of the leading-edge separation bubble; the length of the separation bubble increases as the angle of attack increases. By contrast, the Mach number and specific heat ratio contribute little to the aerodynamic performance. For the NACA 0012-34 airfoil, the lift curves are highly dependent on the Reynolds number because of the formation, shift, and burst of the separation bubble, whereas the compressibility affects only the stall characteristics. The specific heat ratio has little effect on the aerodynamic performance. In common for both airfoils, it was observed that the Mach-number effect allows for the delay of a laminar-turbulent transition and reattachment of the separated shear layer.

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“…It is all known that, for a blade element airfoil, the force coefficients under low-speed free flow are related to not only the angle of attack but also the Reynolds number [21]. And then the force coefficients are just related to angle of attack as the Reynolds number is high enough.…”

Section: Resultsmentioning

confidence: 99%

Performance of Contra-Rotating Propellers for Stratospheric Airships

Tang¹,

Liu²,

Sun³

et al. 2015

International Journal of Aeronautical and Space Sciences

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Small advance ratio and low Reynolds number of stratospheric propulsion system bring lots of challenges to the design of propellers. Contra-rotating propeller configuration is proposed to improve the propulsion efficiency. In this paper, the feasibility of contra-rotating propeller for stratospheric airship has been assessed and its performance has been investigated by wind tunnel tests. The experimental results indicate, at relatively low Reynolds number, although the advance ratio is fixed, the performance of propellers is different with variation of Reynolds number. Moreover, at the same Reynolds number, the efficiency of contra-rotating propeller achieved appears to be a few percent greater than that for a standard conventional propulsion system. It can be concluded that contra-rotating propellers would be an efficient means to improve the performance of stratospheric airship propulsion system.

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Computational and Experimental Analysis of a High-Performance Airfoil Under Low-Reynolds-Number Flow Condition

Cited by 79 publications

References 15 publications

Mechanisms of surface pressure distribution within a laminar separation bubble at different Reynolds numbers

Mechanisms of surface pressure distribution within a laminar separation bubble at different Reynolds numbers

Effects of Mach Number and Specific Heat Ratio on Low-Reynolds-Number Airfoil Flows

Performance of Contra-Rotating Propellers for Stratospheric Airships

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