Numerical Studies of Acoustic Effects on 2D Airfoil Aerodynamics at a Low Reynolds Number

Ikeda, Tomoaki; Atobe, Takashi

doi:10.2514/6.2012-700

Cited by 4 publications

(11 citation statements)

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“…For the symmetric NACA0006 airfoil, vortex shedding patterns drastically change from α = 4°to 5°at M = 0.2, along with the formation of an AFL [10]. With the presence of airfoil camber, similar transition still occurs.…”

Section: Unsteadiness Of Two-dimensional Flowmentioning

confidence: 68%

“…In our previous numerical study [10], airfoil tones were examined for NACA0012, 0006 and 4406 airfoils, by changing angles of attack. Here, primary vortex shedding frequencies are summarized for the present airfoils, sampled at 0.1L above the trailing edge, as well as NACA0006 in Fig.…”

Section: Unsteadiness Of Two-dimensional Flowmentioning

confidence: 99%

“…Airfoil configurations are summarized in Table 1. In addition, an uncambered NACA0006 airfoil is used as a reference [10]. By using a computational code, compressible Navier-Stokes equations are solved.…”

Section: Introductionmentioning

confidence: 99%

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Self-Noise Effects on Aerodynamics of Cambered Airfoils at Low Reynolds Number

Ikeda¹,

Atobe²,

Fujimoto³

et al. 2015

AIAA Journal

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Aerodynamics of cambered airfoils are investigated numerically, using NACA four-digit series of 6% thickness at low Reynolds number Re = 10, 000, and moderate Mach number M = 0.2, by focusing on the relation of aeroacoustic effects and hydrodynamic flow unsteadiness. Two-dimensional numerical simulations show that the onset of an acoustic feedback loop (AFL) leads to an abrupt increase in lift force. Associated with the feedback process, the evolution of two-dimensional vortices in the suction-side boundary layer shifts a separation bubble toward the leading edge, which causes a relatively steep pressure recovery near the trailing edge. Through a parametric study on airfoil shape, the aerodynamically favorable feature of aft camber is further enhanced with the presence of an AFL. In addition, the aft camber airfoil successfully forms a laminar separation bubble in three-dimensional calculations at the present Reynolds number, developing transitional behavior on the suction side, supposedly prompted by the airfoil tones. Although the boundary layer shows three-dimensional complexity, still the formation of an AFL is strongly suggested, via the comparison of spanwise correlations.

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Section: Unsteadiness Of Two-dimensional Flowmentioning

confidence: 68%

Section: Unsteadiness Of Two-dimensional Flowmentioning

confidence: 99%

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Self-Noise Effects on Aerodynamics of Cambered Airfoils at Low Reynolds Number

Ikeda¹,

Atobe²,

Fujimoto³

et al. 2015

AIAA Journal

Self Cite

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“…In a numerical study of one of the present authors [5], trailing-edge noise, generated simultaneously with vortex shedding, causes acoustic resonance via the instability mechanism of separated boundary layer, forming an acoustic feedback loop (AFL). The acoustic pressure is rather amplified due to the resonance, acting as an unsteady force exerted on the surface.…”

Section: Introductionmentioning

confidence: 99%

“…The lower frequency variation has a further impact on the aerodynamic characteristics of airfoil design. Although the presence of airfoil camber reduces the instability of boundary layer [5], an AFL is still prompted by increasing an angle of attack.…”

Section: Introductionmentioning

confidence: 99%

Unsteady Aerodynamic Characteristics of Cambered Four-digit NACA Airfoils at Low Reynolds Number

Ikeda

Fujimoto

Inasawa

et al. 2014

52nd Aerospace Sciences Meeting

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Aerodynamics of cambered airfoils are investigated numerically, using NACA four-digit series at low Reynolds number Re = 10, 000, and moderate Mach number M = 0.2, by focusing on the relation of aeroacoustic effects and hydrodynamic flow unsteadiness. In addition, wind-tunnel experiments are conducted in a regular laboratory environment at very low Mach number for flow a visualization purpose. Two-dimensional numerical simulations show that the onset of an acoustic feedback loop (AFL) leads to an abrupt increase of lift force, shifting a separation bubble toward the leading edge. However, this is not reproduced in a wind-tunnel result with a negligible aeroacoustic effect. Providing 6% thickness, a two-dimensional parametric study on airfoil camber shows that the aft camber location is more favorable to increase attainable lift with less drag. The aft camber also exhibits a better performance in three-dimensional calculations, developing longitudinal eddies on the suction side, which prevents bulk separation. Although the boundary layer shows three-dimensional complexity, still the formation of an AFL is strongly suggested, via the comparison of spanwise correlations.

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Hybridization of a polynomial adaptive high-order solver for unsteady compressible flows

Pereira,

Vermeire

2023

Progress in Canadian Mechanical Engineering. Volume 6

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We present p-adaptive hybridized flux reconstruction schemes to reduce the computational cost of implicit discretizations using a nondimensional vorticity indicator. At each adaptation level, we apply a projection operation to the new space based on the element-wise projected solution and the transmission conditions. We validate our implementation and analyze performance via numerical examples. Specifically, we show that p-adaptation of hybridizable flux reconstruction (HFR) methods results in comparable numerical error to standard p-adaptive and p-uniform standard flux reconstruction (FR) discretizations with a fraction of degrees of freedom. Performance results for a cylinder at Re = 150 showcase speedup factors in excess of 6 for hybridized methods in comparison with p-adaptive standard FR schemes, and up to 40 compared to p-uniform FR discretizations. Similarly, results for a NACA 0012 airfoil at Re = 10, 000 demonstrate speedup factors close to 6 compared to p-adaptive FR discretizations, and up to 33 compared to p-uniform conventional FR. Hence, combinining hybridization with adaptation yields a significant reduction in computatonal cost compared to conventional implicit discretizations.

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Numerical Studies of Acoustic Effects on 2D Airfoil Aerodynamics at a Low Reynolds Number

Cited by 4 publications

References 0 publications

Self-Noise Effects on Aerodynamics of Cambered Airfoils at Low Reynolds Number

Self-Noise Effects on Aerodynamics of Cambered Airfoils at Low Reynolds Number

Unsteady Aerodynamic Characteristics of Cambered Four-digit NACA Airfoils at Low Reynolds Number

Hybridization of a polynomial adaptive high-order solver for unsteady compressible flows

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