Burak Aydogan

3D Numerical Modeling of Stratified Flows: Case Study of the Bosphorus Strait

AbstractThe Bosphorus Strait is a typical example of a narrow sea strait and, in general, has a two-layer flow structure. Driven by the water level difference between the Black Sea (north) and the Sea of Marmara (south), a lighter upper layer flows from north to south. A denser lower layer flow is caused by the density difference between the adjacent seas and flows in the opposite direction. In this study, the three-dimensional (3D) flow structure of the Bosphorus strait was modeled using the MIKE 3 hydrodynamic numerical code. Selecting the drag coefficient (cf), buoyancy parameter (cɛ3), and turbulence Prandtl number (σt) as calibration parameters, the model was calibrated using genetic algorithms with available current measurements at three different depths for one given location. The root-mean-square errors of the calibrated model were calculated to be 0.266, 0.201, and 0.163 m/s at the depths considered, respectively. The model was also validated temporally, for four different time periods and spatia...

How microplastics quantities increase with flood events? An example from Mersin Bay NE Levantine coast of Turkey

Floods caused by heavy rain carry significant amounts of pollutants into marine environments. This study evaluates the effect of multiple floods that occurred in the northeastern Mediterranean region in Turkey between December 2016 and January 2017 on the microplastic pollution in the Mersin Bay. Sampling was repeated in four different stations both before and after the flood period, and it was determined that in the four stations, there was an average of 539,189 MPs/km2 before the flood, and 7,699,716 MPs/km2 afterwards, representing a 14-fold increase. Fourteen different polymer types were detected in an ATR FT-IR analysis, eight of which were not found in samples collected before the floods. The most common polymer type was identified as polyethylene both pre- and post-flood. The mean particle size, which was 2.37 mm in the pre-flood period, decreased to 1.13 mm in the post-flood period. A hydrodynamic modeling study was implemented to hindcast the current structure and the spatial and temporal distributions of microplastics within the study area. In conclusion, heavy rain and severe floods can dramatically increase the microplastic levels in the sea.

Offshore wind power atlas of the Black Sea Region

This study presents an offshore wind power density atlas of the Black Sea Region, including the Black Sea, the Sea of Azov, and the Sea of Marmara, by taking variable air density into account as a function of temperature, pressure, and water content. ECMWF ERA-Interim Reanalysis data spanned over 37 years have been analyzed and monthly average wind speeds, wind speed Weibull scale, and shape parameters, air density, wind power, and operational percentages were presented in the form of maps for 50 m of altitude. Cumulative wind power density frequency maps were generated for 6 percentiles. It is found out that the monthly mean air density has an annual variation of about 9%, which directly affects the available wind power. Results show that the wind power density in the region increases in the West and the North directions, having the maximum potential at the North-West part of the Black Sea and the Sea of Azov. The power density at these locations can be classified as class 4 wind power according to the c...