Abstract: As an important part of the formation of synthetic jet,the design and performance of synthetic jet actuator determine the field and effect of applications of the synthetic jet.How to design it efficiently with low energy consumption to obtain high control efficiency would be the key of synthetic jet applied in active flow control.Based on the study of single beveled orifice syn-thetic jet actuator,the concept of beveled orifices synthetic jet arrays is proposed.The unsteady flow structure of the typical single slit,double slit,the three slit beveled orifices synthetic jet ar-rays were tested with the application of PIV phase-locking technology.And the impact of orifices spacing ratio variation on momentum transport of beveled orifices synthetic j et arrays along the wall was studied.The results showed that,compared with the single slit and double slit,a strong vortex structure and wall-attached jet were formed around the three slit beveled orifices, and the synthetic jet had stronger tangetial velocity distribution along the wall.The flow along the wall was closer to the wall in the three slit beveled orifices,and prone to introduce the high momentum of the fluid in the main flow into the boundary layer at the bottom,thereby increas-ing the underlying energy distribution of the boundary layer.The momentum transport proper-ties of beveled orifices synthetic j et arrays are mainly from the induced effect of vortex and wall-attached jet effect along the wall,and also the flow velocity gradient after coupling of the two effects.Jet orifices spacing ratio is an important parameter affecting the momentum transport of synthetic jet arrays.When the jet spacing ratio is small,the opposite direction of flow velocity gradient difference between the vortex induction and wall-attached j et would be affected by the impact of jet from the first beveled orifice,which will weaken the vortex strength around the sec-ond beveled orifice.Thereby the velocity gradient difference of the flow will be reduced after cou-pling of the vortex and wall-attached jet,which will weaken the induction between the vortex and wall- attached j et .The research results indicated that the beveled orifices synthetic j et arrays will have stronger transporting momentum along the wall when the spacing ratio is 3 .0 .