Abstract: In order to study a new type of plasma synthetic jet actuator with normal slot，the instantaneous flow field characteristics and discharging characteristics were researched by high-speed Schlieren technology and electric parameter measurement system. The results show that the initial jet velocity of normal slot actuator is 1.4 times to that with same exit area normal orifice. While the jet velocity of normal slot actuator tends to damp rapidly and the jet duration is much shorter，which indicate that the momentum exchange between the jet flow and the ambient flow are more violent. Moreover，the three dimensional flow field of normal slot actuator was observed and analyzed firstly，it shows that the precursor shock is more flat and the jet flow has a large uniform portion. Therefore，the normal slot actuator has great advantages in enhancing the work frequency and widening the range of flow control.

Key words: Normal slot；Plasma synthetic jet actuator；Flow control；Uniformity；High initial velocity； Three dimensional flow field

摘要： 为了研究一种新型的直缝式等离子体合成射流激励器，采用高速纹影技术和电参数测量的方法，对激励器的瞬态流场特性和放电特性进行了研究。实验结果表明:在相同出口面积的情况下，直缝式等离子体合成射流激励器的初始射流速度是直孔式激励器的1.4倍。直缝式激励器速度衰减更快，喷气时间更短，和外部气流的动量交换更加迅速。实验中首次对直缝激励器的三维流场进行描述及分析，发现其前驱激波及射流形态具有更好的平面度，存在较大的均匀区。直缝式等离子体合成射流激励器在提高工作频率、扩大流动控制区间等方面具有一定优势。

关键词: 直缝式，等离子体合成射流激励器；流动控制；均匀性；高初始速度；三维流场