Novel Signal Wave Pattern for Efficient Synthetic Jet Generation

A novel signal wave pattern is proposed to generate a more efficient synthetic jet, and the unsteady and mean flow characteristics of the synthetic jet generated by different suction duty cycle factors k are examined by numerical simulation. The mean flowfields of the synthetic jet with different k have similar features to that exhibited in previous experiments, but they would have a stronger and larger scale vortex pair with a larger suction duty cycle factor k, when the two key parameters, the stroke length ratio L 0 /D and the Reynolds number Re U0 (based on the characteristic blowing velocity U 0 and the orifice scale D), are set to be constant. The suction duty cycle factor k affects the vortex strength formed during the blowing cycle only, and nearly does not influence the convection velocity and trajectory of the vortex. During the suction cycle, the entrainment effect of the actuator decreases with the increase of suction duty cycle factor k, so that the vortex pair can propagate farther and coalesce to synthesize a larger scale jet.