EXPERIMENTAL STUDY OF INFLUENCE OF ACTIVE METHODS OF FLOW CONTROL ON THE FLOW FIELD PAST A CYLINDER

摘要

The main emphasis of the paper is placed on the influence of an active method of flow control, as a synthetic jet, on a flow field around a cylinder with an aspect ratio of 1.8. It summarizes the influence of basic factors that affect the design of the synthetic jet actuator, particularly the Strouhal number - nondimensional frequency (F~+), Stokes number of the output orifice (St), Reynolds number (Re), momentum coefficient (c_μ), and a position of the output orifice of the synthetic jet actuator. The actuator is positioned in front of the boundary layer separation. The principle of flow control with and without amplitude modulation was used in order to generate a lower actuating frequency. An amount of input energy of the actuators that influences the flow filed was measured. A change of lift and drag coefficients was calculated from the measured pressure distribution by the model. The alternatives with and without flow control are compared through the relation of the saved up and added energy.