Eulerian Simulations Of Oscillating Airfoils InPower Extraction Regime

A wing that is both heaving and pitching simultaneously may extract energy from an oncoming flow, thus acting as a turbine. The theoretical performance of such a concept is investigated here through unsteady, two-dimensional laminar flow simulations using the finite volume, commercial CFD code FLUENT. Computations are performed in the heaving reference frame of the airfoil, thus leaving only the pitching motion of the airfoil to be dealt with through a rigid-body mesh rotation and a circular, non-conformal sliding interface. This approach offers the benefit of second order time accurate simulations. For a NACA 0015 airfoil at a Reynolds number of Re = 1 100, a heaving amplitude of one chord (H0 = c), and a pitching axis at the third chord (xp = c/3), we present a mapping of power extraction efficiency in the frequency and pitching amplitude domain: 0 55◦ of better than 20% results. Impact of varying some of the fixed parameters is also addressed.