a double - acting device for generating a synthetic jet is provided . the double - acting device includes a chamber having a cavity for a working fluid , a separating element for dividing the chamber into at least two sub - chambers , a control system connected to the chamber for controlling the separating element to act reciprocatingly , an input system connected to the chamber for inputting the working fluid to the chamber therethrough and an output system connected to the chamber for outputting the working fluid from the chamber therethrough . when the working fluid is pushed and pulled by a reciprocating action of the separating element , a train of vortices would be puffed and a non - zero - net - mass - flux fluid is generated through a designed structure and a defined arrangement of the input system and the output system .