Investigation of the effects of alongshore currents on sedimentation processes in coastal inlets
2013
Habibi, Mahdi | Karami Khaniki, Ali
Inlet is an area that fresh water is mixing with ocean salty water and it is a navigation path in coastal zones. The current and sediment transport patterns are two important factors affecting coastline morphology. Subsequently, these factors are influenced by waves and currents. Alongshore currents were generated by waves breaking in the coastal area. Joint Presence of longshore and tidal currents makes the inlet a complex hydrodynamic area. In this research, the effects of tidal and longshore currents on sediment transport pattern and sedimentary features of inlets have been investigated by using numerical modeling. To do this, the junction of a small bay to the open sea, was modeled by MIKE21 software. In this study, different conditions of tide amplitude (0.5, 1.5 and 2.5 meter) and longshore current speed (0.4, 0.6 and 0.8 meter/second) were examined. The result clearly shows two vortexes during transforming from flood to ebb and vice versa. These vortexes in association with tidal flood and ebb currents produce some shallow areas at the sides of the inlet. So, in longshore current, in mouth, entering currents to bay make a vortex. The radius of the tide and longhshore current vortexes and the width of sedimentation area, are directly depend on the tide amplitude and longhshore velocity.
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