Thermal convection analysis of the low Reynolds number flow over an airfoil with simultaneous pitching and plunging motions.

In the literature, several studies have been carried out considering only the hydrodynamic characteristics of pitching and plunging motions. However, the influence of the thermal convection on the aerodynamic performance has not been widely explored. In this study the laminar flow over a NACA0012 airfoil with simultaneous pitching and plunging motions with thermal convection is presented. The non-dimensional, non-steady, two dimensional, Navier-Stokes equations coupled with the energy equation, considering the Boussinesq approximation, are numerically solved by using the spectral element method. The Reynolds number varies from 100 to 1000, while the Rayleigh number is in the range of 1000 to 5x10⁶. For the pitching motion, the amplitude is between 2° and 10°, and the non dimensional reduced frequency varies from 2 to 9. For the plunging motion the non dimensional amplitude varies from 0.0125 to 0.045, and the reduced frequency range is the same as for the pitching motion. It is found that an increase of the Rayleigh number has an adverse effect on the aerodynamic performance. A three dimensional map involving the Reynolds and Rayleigh numbers and the reduced frequency shows the behaviour of the aerodynamic performance and the heat transfer rate.