Dynamics of laminar separation bubble over NACA-0012 airfoil near stall conditions

Almutairi, Jaber H.; ElJack, Eltayeb; AlQadi, Ibraheem

doi:10.1016/j.ast.2017.05.015

Cited by 30 publications

(12 citation statements)

References 23 publications

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“…By examination at the flow field structure, in contrast to vortex-merging in the LSBs for Reynolds number at 30,000, a stabilized separation bubble is captured at Reynolds number of 60,000, which a single and large separation bubble structure is clearly shown in Figure 9 (a-g). A separation bubble with similar structures and development process was also confirmed by other investigators at various Reynolds numbers, regardless of whether the bubble is formed over a flat plate subjected to an adverse pressure gradient or an airfoil 39 . The pressure distribution can also confirm the trend of the LSBs development trend for Reynolds number of 60,000 in Figure 8 (b), which shows a reduced length on pressure plateau with increased value on suction force.…”

Section: Laminar Separation Bubbles For a Fixed Airfoil At Different Incidences For Re=30000 And 60000supporting

confidence: 79%

Laminar separation bubble dynamics and its effects on thin airfoil performance during pitching-up motion

Chen

Xiao

Wang

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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This article reports an investigation into dynamic characteristics of the laminar separation bubbles (LSBs) associated with aerodynamic loads unsteadiness of a cambered thin airfoil in pitching-up motions at low Reynolds number flows. Unsteady Reynolds-averaged Navier–Stokes (URANS) simulations were conducted for a 4%c cambered thin airfoil at Reynolds number of 30,000 and 60,000. The airfoil pitches up from 0° to 25°angles of attack at dimensionless pitch rate [Formula: see text] of 0.0398 and 0.0199. The [Formula: see text] SST [Formula: see text] turbulence transition model was used to account for the effect of transition on LSBs’ development. The LSBs are shown to evolve in their shape and size during the pitching motion. The influence of the LSBs on the airfoil upper surface during pitching motion continues to a higher incidence in comparison with that under static conditions before developing into a fully detached flow. Vortex merging is observed in the rear part of the LSBs in the turbulent portion for a Reynolds number of 30,000. At Reynolds number 60,000, the changing of the LSB length during pitching-up motion is similar to that of steady cases, except a delayed transition is observed as incidence increases. The results show further insight into the dynamic characteristics of the LSBs and their relation to the aerodynamic performance of the airfoil.

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Section: Laminar Separation Bubbles For a Fixed Airfoil At Different Incidences For Re=30000 And 60000supporting

confidence: 79%

Laminar separation bubble dynamics and its effects on thin airfoil performance during pitching-up motion

Chen

Xiao

Wang

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…This symmetry helps the effects produced by the TEFs to be understood and shown more clearly. Recent studies carried out by Di et al [29] and Al Mutairi et al [30] show that NACA 0012 airfoil is still of interest of to the scientific community.…”

Section: Aims and Methodologymentioning

confidence: 99%

A Parametric Study of Trailing Edge Flap Implementation on Three Different Airfoils Through an Artificial Neuronal Network

et al. 2020

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Trailing edge flaps (TEFs) are high-lift devices that generate changes in the lift and drag coefficients of an airfoil. A large number of 2D simulations are performed in this study, in order to measure these changes in aerodynamic coefficients and to analyze them for a given Reynolds number. Three different airfoils, namely NACA 0012, NACA 64(3)-618, and S810, are studied in relation to three combinations of the following parameters: angle of attack, flap angle (deflection), and flaplength. Results are in concordance with the aerodynamic results expected when studying a TEF on an airfoil, showing the effect exerted by the three parameters on both aerodynamic coefficients lift and drag. Depending on whether the airfoil flap is deployed on either the pressure zone or the suction zone, the lift-to-drag ratio, CL/CD, will increase or decrease, respectively. Besides, the use of a larger flap length will increase the higher values and decrease the lower values of the CL/CD ratio. In addition, an artificial neural network (ANN) based prediction model for aerodynamic forces was built through the results obtained from the research.

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“…Many researchers have numerically and experimentally investigated the aerodynamic performance of airfoil. The dynamics of laminar separation bubble over an airfoil near stall conditions using large eddy simulation of flow around NACA-0012 airfoil at an angle of attack for a Reynolds number and Mach number was investigated by [1]. They found that that computed Strouhal number of the oscillation was in good agreement with the experimental data where a selfsustained low-frequency flow oscillation was observed.…”

Section: Introductionmentioning

confidence: 91%

A Comparative Study of Turbulence Models on Aerodynamics Characteristics of a NACA0012 Airfoil

Sadikin

Yunus²,

Hamid³

et al. 2018

IJIE

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This paper presented a computational fluid dynamics (CFD) simulation of air flow past a 2D model NACA0012 airfoil at high Reynolds number (Re = 3.0 x 10 6 ) at various angles of attack (-10 to 15). The simulations were undertaken to inform on how the fluid flowed around the airfoil by solving the steady state governing equations of continuity and momentum conservation that are combined with one of three turbulence models Spalart-Allmaras, Realizable k-ε and k-ω shear stress transport (SST). It is observed that the Realizable k-ε eliminates the small separation bubble on the upper surface of the airfoil and delaying separation flow. Also, for the lift coefficient, CL and drag coefficient, CD investigated in this paper, the predicted data have good agreement with other published data.

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Dynamics of laminar separation bubble over NACA-0012 airfoil near stall conditions

Cited by 30 publications

References 23 publications

Laminar separation bubble dynamics and its effects on thin airfoil performance during pitching-up motion

Laminar separation bubble dynamics and its effects on thin airfoil performance during pitching-up motion

A Parametric Study of Trailing Edge Flap Implementation on Three Different Airfoils Through an Artificial Neuronal Network

A Comparative Study of Turbulence Models on Aerodynamics Characteristics of a NACA0012 Airfoil

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