Numerical Study on Thrust Generation in an Airfoil Undergoing Nonsinusoidal Plunging Motion

AbstractFor the last few decades, an extensive research has been focused on flapping-wing aerodynamics to understand the generation of thrust due to pitching and plunging motions of an airfoil. However, most of the research emphasized an airfoil undergoing simple harmonic motion in either pitching or plunging motion. In this paper, a numerical study has been performed to estimate the thrust generated from a NACA0012 airfoil undergoing a periodic motion. The prescribed motion is created by an expression for harmonic and nonharmonic but periodic motions. The effects of these prescribed motions on thrust generation have been studied numerically for a Reynolds number of 20,000. It is observed that the thrust generated by the square and trapezoidal (periodic) plunging motions is much higher than the sinusoidal (harmonic) plunging motion. The effects of reduced frequency and amplitude of oscillations on the generation of thrust have also been studied. At higher reduced frequency and amplitudes, trapezoidal plunging motion generates higher thrust.