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对不同出口间距零质量射流组的流场结构进行了PIV实验.采用相位锁定技术测量了周期内不同相位的瞬时流场速度矢量,显示了两股射流涡对之间相互作用、融合成为一股射流的全过程.发现射流出口间距越大,射流组融合完成所需的时间、空间历程越长.在射流组融合完成后的下游截面上,速度分布和单射流相似,具有自模性.虽然融合未完成前各截面不存在整体自模性,但两股射流外侧仍满足自模性.
PIV experiments were carried out on the flow field structures of zero-mass jet groups with different exit pitches. The phase-locked technique was used to measure the instantaneous flow field velocity vectors of different phases in the period, showing the interaction between the two jet vortices. It is found that the larger the jet exit spacing is, the longer the space required for the jet group to fuse is and the longer the space history is. The velocity distribution is similar to a single jet in the downstream section after the jet group is fused, and has self-moldability. Before the completion of the fusion, the overall self-molds did not exist in all the sections, but the outer sides of the two jets still satisfied the self-moldability.