Assessment of Current Power Potential of the Two-Layer Exchange Flow through the İstanbul Strait (Bosphorus) Using a 3D Hydrodynamical Model

The density-driven flow has complex dynamics, including hydraulic controls, internal hydraulic jumps, and significant mixing at the interface.The Bosphorus is an example of the maximal-exchange regime, where hydraulic controls at the contraction and the northern sill govern the two-layer exchange [2,5-9].This two-layer exchange has a mean annual barotropic flow of ~300 km³/yr toward the Sea of Marmara, sustained by the AbstractThe power potential of the the two-layer exchange flow in the İstanbul Strait (Bosphorus) was assessed using a 3D hydrodynamic model that resolves the full geometry of the strait.Steady-state solutions for the mean annual barotropic flow rate under both homogeneous and stratified reservoir conditions were used to quantify the advective transport of kinetic energy in the upper and lower layers.Results indicate substantial energy availability, with peaks in the southern strait in the upper layer and downstream of the northern sill in the lower layer, and these peaks persist under both hydrographic conditions.Under stratified conditions, power densities from the upper layer reach up to 3.84 kW/m 2 but remain confined to the upper 10 m and overlap with heavy marine traffic, limiting practical harvesting in the narrow southern section.The lower layer peak effective kinetic energy flux accounts only 35% of the upper-layer peak yet achieves comparable power densities of up to 2.69 kW/m 2 just after the northern sill.Simulations with varying barotropic flow rates under stratified reservoir conditions show limited variability in the lower-layer peak section before the hydraulic jump following the north sill, where harvesting attempts could affect the exchange dynamics, and strong variability in the second peak farther downstream, where impacts on the Mediterranean effluent may have ecological consequences.