EXPERIMENTAL STUDY ON AERODYNAMIC LOAD CONTROL USING SYNTHETIC JET ACTUATORS

摘要

This paper addresses the use of piezo-electric driven synthetic jet actuators as aerody-namic load control device in a 2D wing wind-tunnel model with a NACA0018 airfoil section with a chord of 0.165 m. Synthetic jets can be integrated in for instance wings and wind tur-bine blades to alleviate load variations and therewith reduce risk of fatigue damage. Compared to other flow control devices, syn-thetic jet actuators are favorable due to their small response time and low power require-ments. A synthetic jet actuator from literature has been redesigned in order to fit inside the present airfoil section, at a location as closely as possible to the trailing edge of the airfoil. The jet exits from a narrow slot in the direction perpendicular to the surface of the airfoil. First, a prototype version of this redesigned actuator was manufactured and the jet velocity was mea-sured using hot-wire anemometry. These mea-surements show that maximum centerline jet velocities up to 45 m/s can be achieved at an optimum actuation frequency of 700 Hz. Next, a non-swept 2D NACA0018 wing fitted with a module containing ten span wise distributed actuators was designed and manufactured. Wind tunnel tests have been performed in an open return wind tunnel at the University of Twente with a closed test section of 0.455 m by 0.455 m in cross section. The obtainable varia-tion in the lift coefficient of the wing was mea-sured, within some range of the actuation parameters. The highest relative increment in lift coefficient of 0.06 was obtained for a free-stream velocity of 12.4 m/s, combined with an actuation frequency of 750 Hz, corresponding to a reduced frequency of 10.