Micro-scale synthetic-jet actuator flow simulation with characteristic-based-split method

摘要

Purpose - The purpose of this paper is to present a computational study to investigate the effects of rectangular cavity design of a piezoelectricallyrndriven micro-synthetic-jet actuator on generated flow.rnDesign/methodology/approach - Flow simulations were done using a compressible Navier-Stokes solver, which is based on finite element methodrnimplementation of a characteristic-based-split (CBS) algorithm. The algorithm uses arbitrary Lagrangian-Eulerian formulation, which allows to modelrnoscillation of the synthetic jet's diaphragm in a realistic manner. Since all simulated flows are in the slip-flow-regime, a second order slip-velocityrnboundary condition was applied along the cavity and orifice walls. Flow simulations were done for micro-synthetic-jet configurations with variousrndiaphragm deflections amplitudes, cavity heights, and widths. All of the simulation results were compared with each other and evaluated in terms ofrnthe exit jet velocities, slip-velocities on the orifice wall and instantaneous momentum fluxes at the jet exit.rnFindings - It is shown that compressibility and rarefaction have important effects on the flow field generated by the micro-synthetic-jet actuator. Therneffect of the geometrical parameters of the cavity to important flow features such slip and phase lag are presented.rnOriginality/value - The paper reports results of a systematical study of the flow field inside a micro-scale synthetic-jet actuator, providing designers ofrnsuch devices additional information for sizing the cavity within slip flow regime. Furthermore, it is demonstrated that the CBS, together with sliprnboundary conditions can be successfully used to compute such flows.