Numerical Study on Low Reynolds Number Flows Over an Aerofoil

Karasu, İlyas; Genç, Mustafa Serdar; Açıkel, Halil Hakan

doi:10.4172/2168-9873.1000131

Cited by 5 publications

(3 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: 95%

“…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: 95%

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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“…NACA airfoils have been the research subject of many studies due to their widespread use in practice [8][9][10][11][12][13]. Lee et.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Riblets on the Aerodynamic Performance of NACA 0018 Airfoil

Güler,

Pınar,

Durhasan

2024

Çukurova Üniversitesi Mühendislik Fakültesi Dergisi

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In this numerical study, riblets on the airfoil were utilized to enhance the aerodynamic performance of NACA0018 airfoil. Riblets of identical height and base length are strategically placed on the suction surface of the airfoil with varying spacing ratios along the flow direction (x) and chord length (c), specifically x/c = 0.3 and 0.7. Four distinct riblet airfoil models are subjected to computational fluid dynamics (CFD) analysis within an angle of attack range from 0° to 21° at a Reynolds number of Re=1×105. The obtained results are systematically compared with the performance of the plain airfoil. Numerical analyses reveal the significant influence of the spacing ratio on flow control and the overall aerodynamic performance of the airfoil, establishing a direct relationship with riblet spacing. The presence of riblet structures is observed to increase the lift coefficient, concurrently delaying the stall angle up to 19°. Notably, the ribbed structures effectively mitigate the interaction between the laminar separation bubble and trailing edge separation, leading to a reduction in turbulent kinetic energy values.

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Characteristics of Boundary-Layer Transition and Reynolds-Number Sensitivity of Three-Dimensional Wings of Varying Complexity Operating in Ground Effect

Roberts

Finnis

Knowles

2016

Journal of Fluids Engineering

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The influence of Reynolds number on the aerodynamic characteristics of various wing geometries was investigated through wind-tunnel experimentation. The test models represented racing car front wings of varying complexity: from a simple single-element wing to a highly complex 2009-specification formula-one wing. The aim was to investigate the influence of boundary-layer transition and Reynolds-number dependency of each wing configuration. The single-element wing showed significant Reynolds-number dependency, with up to 320% and 35% difference in downforce and drag, respectively, for a chordwise Reynolds number difference of 0.81 × 105. Across the same test range, the multi-element configuration of the same wing and the F1 wing displayed less than 6% difference in downforce and drag. Surface-flow visualization conducted at various Reynolds numbers and ground clearances showed that the separation bubble that forms on the suction surface of the wing changes in both size and location. As Reynolds number decreased, the bubble moved upstream and increased in size, while reducing ground clearance caused the bubble to move upstream and decrease in size. The fundamental characteristics of boundary layer transition on the front wing of a monoposto racing car have been established.

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Numerical Study on Low Reynolds Number Flows Over an Aerofoil

Cited by 5 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

The Effect of Riblets on the Aerodynamic Performance of NACA 0018 Airfoil

Characteristics of Boundary-Layer Transition and Reynolds-Number Sensitivity of Three-Dimensional Wings of Varying Complexity Operating in Ground Effect

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