New Experimental Apparatus for the Study of the Unsteady Flowfield over anAirfoil in Pitching and Heaving Motions Using Laser Doppler Anemometry

摘要

An experimental setup used for the study of the flowfield over an airfoilundergoing arbitrary pitching or heaving motions is described. This setup is basically composed of two parts: a novel driving mechanism, based on an automatic apparatus, two speed drives, two brushless motors and a support system, which allows the airfoil to be put into a wide range of periodic or transient motions and a classical two dimensional laser Doppler anemometry system which provides streamwise and transversal components of the velocity. Data acquisition, data reduction and synchronization problems are discussed. Results concerning dynamic stall features observed in the near wake of a pitching airfoil at a Reynolds number of 287,000 are given.