The flow field characteristic structure of steady and pulsed jet impinging on the target plate was investigated. High frequency particle image velocity measurement technology was used to measure a steady jet and a pulsed jet with a frequency of 20 Hz. Besides

the distance between the jet nozzle and the target plate was 6 times the diameter of the nozzle

and the steady jet inlet Reynolds number was 6 000 for both steady and pulsed jet flows. The experiment obtained velocity distribution of the core jet zone

the wall jet zone

and the stagnation zone. The results show that: (1) due to the shear action of the jet

maximum axial fluctuation velocity in the core jet zone of the pulsed jet was nearly three times that of the steady jet. (2) In the stagnation zone

the maximum gradient of the axial velocity of the pulsed jet was approximately twice that of the steady jet

which resulted from the shear action of the jet and the stagnation action of the wall. Furthermore

the maximum fluctuation velocity in the stagnation zone was nearly three times that of the steady jet. (3) The entrainment of the pulsed jet and the propagation of the vortex led to the destruction of the velocity boundary layer in the wall jet region. Compared with the steady jet

the flow field of the pulsed jet increased the energy of the turbulent coherent structure and generated periodic large-scale vortex.