Title: Computational investigation of low-Reynolds-number unsteady flows past NACA 0012

Authors: Mertcan Güney; Berkan Anilir; Dilek Funda Kurtulus

Addresses: Aerospace Engineering Department, Middle East Technical University, Ankara, 06800, Turkey ' Aerospace Engineering Department, Middle East Technical University, Ankara, 06800, Turkey ' Aerospace Engineering Department, Middle East Technical University, Ankara, 06800, Turkey

Abstract: The aerodynamic characteristics of airfoils are significantly governed by the Reynolds number, particularly in the low Reynolds number regime (Re < 1 × 10⁵), where viscous forces predominate over inertial forces, promoting early boundary layer separation and transition to turbulence. This study conducts two-dimensional unsteady numerical simulations on a NACA 0012 airfoil across Reynolds numbers ranging from 4 × 10⁴ to 1 × 10⁵, with the angle of attack varied incrementally from 0° to 20°. The results reveal that lower Reynolds numbers and higher angles of attack induce premature flow separation, leading to a diminished lift coefficient and an increased drag coefficient due to the altered separation point dynamics.

Keywords: NACA 0012; unsteady aerodynamics; low Reynolds number; computational fluid dynamics.

DOI: 10.1504/PCFD.2026.151116

Progress in Computational Fluid Dynamics, An International Journal, 2026 Vol.26 No.1, pp.32 - 47

Received: 18 Mar 2025
Accepted: 01 May 2025
Published online: 14 Jan 2026 *

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