An investigation into the effects of unsteady parameters on the aerodynamics of a low Reynolds number pitching airfoil

• Published in: Journal of fluids and structures Vol. 26; no. 6; pp. 979 - 993
• Main Authors: Amiralaei, M.R., Alighanbari, H., Hashemi, S.M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-08-2010; Elsevier
• Subjects: Aerodynamics; Applied fluid mechanics; CFD; Computational fluid dynamics; Exact sciences and technology; Fluid dynamics; Fluid flow; Fundamental areas of phenomenology (including applications); General theory; Lift; Low Reynolds number; Mathematical models; Navier-Stokes equations; Physics; Pitching airfoil; Unsteady; Unsteady aerodynamics; CFD; Low Reynolds number; Pitching airfoil; Unsteady aerodynamics; Pitching; Computational fluid dynamics; Reynolds number; Aerodynamics; Airfoils; Unsteady flow; Finite volume methods; Optimization; Hysteresis loop; Wing beat; Kinematics; Modelling; Vortex flow; Navier-Stokes equations
• ISSN: 0889-9746; 1095-8622
• DOI: 10.1016/j.jfluidstructs.2010.06.004

The growing applications of low Reynolds number (LRN) operating vehicles impose the need for accurate LRN flow solutions. These applications usually involve complex unsteady phenomena, which depend on the kinematics of the vehicle such as pitching, plunging, and flapping of a wing. The objective of the present study is to address the issues related to LRN aerodynamics of a harmonically pitching NACA0012 airfoil. To this end, the influence of unsteady parameters, namely, amplitude of oscillation,
d, reduced frequency,
k, and Reynolds number, Re, on the aerodynamic performance of the model is investigated. Computational fluid dynamics (CFD) is utilized to solve Navier–Stokes (N–S) equations discretized based on the Finite Volume Method (FVM). The resulting instantaneous lift coefficients are compared with analytical data from Theodorsen’s method. The simulation results reveal that
d,
k, and Re are of great importance in the aerodynamic performance of the system, as they affect the maximum lift coefficients, hysteresis loops, strength, and number of the generated vortices within the harmonic motion, and the extent of the so-called figure-of-eight phenomenon region. Thus, achieving the optimum lift coefficients demands a careful selection of these parameters.