engleski

Enhancement of mixing processes in semi-deep coastal channels by a bathymetry change

Recent investments in construction of a number of submarine outfalls in Croatia pushed the local scientific community to focus attention to hydrodynamics of numerous stratified semi-deep (60-80 m) coastal channels in the Eastern Adriatic, which are planned to receive important quantities of partially treated wastewater in the near future. In some cases, however, simple channel geometry is complicated by bottom irregularities which are suspected to be the main cause of enhancement of mixing rates between different layers of stratified fluid. As a consequence, partial or complete destruction of typical density stratification can result in sur-facing of intermediate layers, where trapping of wastewater mixture is expected in normal oceanographic conditions. In order to examine hydrodynamics in the zone affected by a bathymetry change, the 3-D numerical model has been set up and tested in the channel where sea bottom irregularity, extending perpendicularly to the shore, encompasses one half of the channel width. Beside phenomenological description of this type of stratified flow, obtained re-sults are compared with known functional relationships governing turbulent interfacial mixing in layered flows.

Stratified flows in semi-deep coastal channels; impact of submerged reefs; mixing in stratified water column

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