Flow around a rigid oscillating airfoil undergoing nonlinear oscillations in persistent and pulsating currents

The flow over an oscillating airfoil following harmonic and nonlinear oscillations is numerically studied. Motivated by the design of energy harvesting device components, different sets of parameters are considered to vary the airfoil oscillations and flow characteristics in the Reynolds number range 200≤Re≤500. Results on the vortex shedding patterns and the resulting forces on the airfoil are included. Additionally, for the case of harmonic oscillations, the effect of a pulsating current is analyzed. The characteristics of this current are determined by a downscaling procedure based on field measurement data in the Cozumel channel, Mexico. Results show the importance of including such characteristics in the study of the hydrodynamic forces on the airfoil. Flow instability is observed in the wake behind the oscillating foil for specific parameter combinations.