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.
Highlights
With the fast development of industrial economy and the large growth of population at the coastal cities, the marine environment in coastal and offshore areas has been greatly deteriorated
Afterwards, the effluent is discharged as horizontal jets, vertical jets, inclined jets, and so on, into the coastal waters from a multiport diffuser at the bottom of the receiving water, which is mostly predominated by wave and current environment
This study considered the experimental conditions of twin buoyant jets in the cross-flow-only environment for comparison
Summary
With the fast development of industrial economy and the large growth of population at the coastal cities, the marine environment in coastal and offshore areas has been greatly deteriorated. The related pollutants are potential threat to the local marine environmental and ecological systems [1]. The coastal sewage disposal project turns to be one of the available solutions to this problem in maintaining the coastal and offshore marine environment. As an environmentally friendly management practice, the effluents are treated in such a manner that local concentration levels are reduced to the maximum possible extent and the adverse effects are minimized before being discharged into the coastal and offshore waters. According to Fan [5], the density of outfall discharges is very close to that of pure water, which is lighter than the seawater. Most of the outfall discharges can be regarded as positive buoyant jets
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
