Author(s): B. Y. F. Tam; C. W. Li
Linked Author(s): Chi Wai Li
Keywords: Jets; Random waves; Jet-wave interaction
Abstract: An experimental study of jets under random surface waves was carried out. A submerged vertical turbulent jet was installed at the bottom of a laboratory wave flume equipped with a random wave generator. Propagating random waves with JONSWAP spectra were generated to interact with the jet. An acoustic Doppler velocimeter (ADV) was employed to measure the velocity within the jet body. Time-averaged experimental data were scaled with proper parameters for analysis. The results show that the jet centerline velocity profile can be divided into two regions, the jet-momentum dominated near field (JDNF) and the wave-momentum dominated far field (WDFF). The jet width varies linearly with the distance from the jet outlet within the JDNF and nonlinearly within the WDFF. The radial velocity profiles generally follow the normal distribution curve. The results also show that waves cause a shift of the location of peak turbulence towards the jet outlet. The extent of shift in location depends on the wave properties, showing that the jet turbulence is generated by both the wave motion and the jet motion.