Spectral analysis of the boundary layer on a plunging airfoil

Abstract

Paper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.

The effects of periodic unsteady flow through plunging motion on the boundary layer transition along the suction surface of a typical wind turbine blade section are experimentally investigated The state of the boundary layer at different conditions was determined using multiple hot-film sensors through the frequency domain analysis. The appearance of laminar/turbulent spikes at dominated frequencies revealed the boundary layer characteristics. Power spectral of the hot­-film signals showed that the transition locations as well as the separation region were a function of the reduced frequency and mean angle of attack.