Numerical study of nozzle design for the hybrid synthetic jet actuator

• Five hybrid synthetic jet actuators have been numerically studied.
• Flow interactions between cavities in an operating cycle are concentrated.
• The internal vortex plays essential roles on flow mass exchange.
• Submerging the height of central nozzle wall can increase volumetric efficiency.
• More than six times net flow volume can be enhanced by the best design.

This paper presents a numerical study on the influence of the geometrical arrangement of the hybrid synthetic jet (HSJ) actuators. We study five variants of the HSJ actuators. The laboratory experiment by using water as the working fluid has been conducted for comparison and validation of the numerical simulation. The numerical results reveal the formation and propagation of vortices during the operating cycle in detail. It is identified that the internal vortex within the HSJ actuator plays essential roles on the flow mass exchange during the operating cycle. Our results show that the flow pattern of synthetic jet is highly sensitive to the internal geometrical design, which leads to significant difference in efficiency for different actuators.