2D PIV Measurement of Twin Buoyant Jets in Wavy Cross-Flow Environment

Abstract

The multiport diffuser effluent discharge facilities constructed beneath the coastal waters were simplified in the laboratory as twin buoyant jets in a wavy cross-flow environment. The near-field flow structure of twin jets was studied by series of experiments conducted in a physical wave–current flume. The particle image velocimetry (PIV) system was used to measure the velocity field of the jets in various cross-flow-only and wavy cross-flow environments. By means of flow visualization, the distinctive “effluent cloud” (EC) phenomenon was clearly observed and the jet penetration height was found to be notably increased compared with that of cross-flow-only environment at the downstream position. It was found that the wave-to-current velocity ratio Rwc is a very important parameter for effluent discharge. A new characteristic velocity uch and the corresponding characteristic length scale lmb for twin buoyant jets in the wavy cross-flow environment were defined. Using curve-fitting, a new equation to estimate the effects of the jet-to-current velocity ratio (Rjc), wave-to-current velocity ratio (Rwc) and Strouhal number (St) on the jet trajectory were derived to enhance understanding the physical processes underpinning the rise and the dilution of buoyant jets, which is critical to the design of discharge facilities.

Numerical Modeling of Multiple Inclined Dense Jets Discharged from Moderately Spaced Ports

“…Most of the previous studies on multiple jets were conducted using experimental methods. These studies can be classified into three categories depending on the angle at which the jets were discharged into the receiving water bodies: Horizontal [9][10][11][12], vertical [8,13], and inclined [2][3][4][14][15][16]. These studies are very important for advancing the understanding of multiple jets, but it is widely accepted that experimental tests are expensive and time-consuming, and thus developing supplementary tools is meaningful.…”

Transport dynamics of sediment‐laden jet: A review

“…According to previous studies on pure jet streams (Figure 12), the movement and diffusion laws of jet streams under a wavy current environment are quite different from those in still water or in a constant cross‐flow environment (Chen et al, 2008, 2012; Fang et al, 2019; Otoo et al, 2019, 2022; Y. Wang et al, 2015; Xu et al, 2016, 2017, 2018, 2019, 2020), which will inevitably have a significant impact on the movement of sediment particles in the sediment‐laden jet. Therefore, to fully capture the true movement of the sediment‐laden jet under the marine dynamic environment, the interaction between sediment‐laden jet flow with wave and current needs to be tackled.…”

“…(Chen et al, 2008(Chen et al, , 2012Fang et al, 2019;Otoo et al, 2019Otoo et al, , 2022Y. Wang et al, 2015;Xu et al, 2016Xu et al, , 2017Xu et al, , 2018Xu et al, , 2019Xu et al, , 2020, which will inevitably have a significant impact on the movement of sediment particles in the sediment-laden jet. Therefore, to fully capture the true movement of the sediment-laden jet under the marine dynamic environment, the interaction between sediment-laden jet flow with wave and current needs to be tackled.…”

Waterbodies thermal energy based systems interactions with marine environment — A review

“…Followed on, Xu et al (2018) developed a set of semi-empirical equations to quantify the wave effect on the initial dilution of wastewater discharge based on numerical modelling of non-buoyant jet discharges in wave-followingcurrent environments. This is extended in Xu et al (2019) where they conducted several experimental tests about submerged multiport diffuser effluent discharges in a wavy cross-flow environment. It was discovered that the wave-to-current velocity ratio is a very important parameter in describing effluent discharge dilution.…”