Investigating of Simulation Methods for Synthetic Jet

Periodic velocity inlet and dynamic mesh boundary conditions are always used to simulate oscillatory piston of synthetic jet. Periodic velocity inlet condition is an easy way to simulate oscillation of membrane of synthetic jet, and dynamic mesh boundary condition is a realistic method using moving grid to simulate the motion of piston, but it needs more computing time because of updating the new grid topology at every time step. In this paper, the two methods’ influence for synthetic jet simulation is investigated, and two cases with different boundary conditions are conducted respectively in low Reynolds number laminar flow. The results show that the velocity profiles near the orifice are different distinctly on 0° and 180° phase, the max speed difference at center of orifice is about 0.017 m/s at the end of third period, which increased by 150% of the simulating results with dynamic mesh boundary method. On the other hand, the vortex dye-structure is a little different near the oscillating membrane located at the cavity bottom though it is same commonly outside of synthetic jet when using the two simulation methods. The simulation method with dynamic mesh is more reasonable because it is realistic motion of piston in fact, and the time cost is not more heavily than velocity inlet boundary condition.