Resumen

MONTERO, Mariana, Montenegro  y  NAVARRO, Gustavo, Richmond. Laminar separation bubbles on the transitional flow around airfoils. Rev. cienc. tecnol. [online]. 2022, n.38, pp.1-10. ISSN 1851-7587.  http://dx.doi.org/10.36995/j.recyt.2022.38.001.

The purpose of this work is to apply the g-Req turbulence model, which is one of the numerical methods of shear stress transport (SST) applicable to transient flow, to examine if it shows the expected laminar separation cells or bubbles. This condition is key in the way to guarantee that the numerical modeling of lift and drag forces in aerodynamic profiles is more faithful to corresponding experimental data. For this, several two-dimensional simulations implemented with OpenFOAM, a well-known Finite Volume Method (FVM) package, were carried out for a Reynolds number range between 1x104 and 5x105, with the airfoils NACA0012, SG6043 and S826, in which the laminar separation bubbles usually form. Numerical results of lift and drag coefficients show correct prediction of experimental results and error is reduced by 3% when compared to other simulations. In particular, adequate performance of the model is observed for regions close to or greater than the angle of attack for which the aerodynamic profile stalls. On the other hand, the geometric footprint of the flow simulated with this g-Req transition SST model shows great improvement compared to previous studies regarding the formation of laminar separation bubbles, which in turn means better performance when calculating lift and drag coefficients. It is also concluded that laminar separation occurs in the three studied airfoils, being symmetric or asymmetric profiles.

Palabras clave : Airfoil performance; Turbulence model; Transitional flow; Finite Volume Method; Laminar separation bubble; Reynolds number; Intermittency.

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