Abstract:The near-field velocity and concentration fields of vertical multiple jets in wavy cross-flow were measured by using the PIV and PLIF techniques. The characteristics of multiple jets, including the trajectory, velocity field, concentration field and vorticity field, were analyzed, focusing on the differences between the jet in wavy cross-flow and that in cross-flow as well as the wave effect on the development of multiple jets. The results show that the time averaged trajectories of jets in wavy cross-flow are distorted with “effluent cloud” existing on the jet body. Further, wave has a significant influence on the movement of multiple jets in wavy cross-flow, including increasing the interaction area between jets and surrounding waters, accelerating the decay of the vertical momentum of jets, enhancing the shielding effect of leading jet on the rear jets, and reducing the height of the confluent point of the jets, etc. In present cases, waves lead to the decreasing of the peak concentration of contaminant at all sections, and thus have a positive effect on the dilution of multiple jets in wavy cross-flow.