Abstract: Disposal of sewage into the oceans is a typical jet movement. As jet flows, the reciprocal motion of water generated by waves obviously restricts the formation and development of jet. However, less research has been done to study the interaction between jet and waves. In this article, physical model test of dual jets under wave action is conducted by using digital pressure sensor to analyze the pressure distribution and axial attenuation law of dual jet cross-section under wave action. The experimental results show that the pressure distribution of dual jets cross-section under wave condition is similar to that in hydrostatic condition, but the jet pressure under wave condition is larger than that under hydrostatic condition; the larger the wave period is, the greater the pressure peak value increases. The development of the dual jets has undergone single-hole-dominated, double-hole jet adsorption and blending, as well as merging processes. In the single-hole-dominated zone, the distribution of jet pressure is similar to that in hydrostatic condition; in the adsorption and blending zone, pressure attenuation in the holes varies, namely, pressure attenuation in the first hole is similar to that of single-hole jet, and the second hole smaller than that of the first hole; in the merging zone, the dual jets merge into one, with the hydrodynamic characteristics similar to that of a single-hole jet. Moreover, wave has a positive effect on the blending of dual jets, and the effect intensifies with the elongation of wave period, which also makes the jet merge section appear earlier, indicating that wave period has a significant influence on jet pressure.

Key words: dual jets, pressure characteristics, digital pressure sensor, wave action, wave period