Flow patterns of zero-net-mass-flux jets and parameters
Details
Zero-net-mass-flux (Synthetic) jets are produced by the back-and-forth motion of a piston. Synthetic jet flow experiments using PFV were conducted to characterize the flow. Phase-averaged vorticity fields, which are synchronized with the movement of the piston, have been calculated from velocity vector fields. Jet flow patterns are classified into four different categories. These four categories are identified from the iso-vorticity contours and fluorescence dye flow visualization images, and the classification of the patterns is shown in the Reynolds number versus Strouhal number plot. Three different categories, Flat type, Ramp type, and Sine type, where the mean velocity through the orifice was varied with respect to time are investigated. It is found that the Sine type velocity variation is proper to produce the flow pattern of "laminar vortex rings."
