Abstract
Over the last decade, synthetic jets adequate for micro machinery have received attention as substitutes for continuous jets. The development of synthetic jet actuators with, for example, a diaphragm, a piston, or a speaker cone, instead of mechanical drivers, is required for the downsizing of flow control systems in fluid machines. In this study, an experimental prototype of a synthetic jet actuator using the nonlinear oscillation of bubbles produced by iterative electric discharge is proposed. Numerical simulations clarify the fundamental flow characteristics of the synthetic jets produced by ideal bubble oscillation. The discharge conditions include the influence of the metal particle concentration in liquid on bubble generation. The onset condition based on the non-dimensional stroke of the synthetic jet and the relation between the bubble motion and the change of the jet velocity with time are discussed. Especially, the influence of T* (the ratio of driving time of a bubble to the down time) on the unsteady flow pattern and the time-averaged jet structure is investigated. In addition, the flow characteristics of a synthetic jet with down time are compared with that of a normal synthetic jet with equivalent velocity.
