Effects of Flow and Ebb Tides on the Current and Sediment Transport Patterns in Deltas Using the Numerical Mike 21 Software

Subject Areas : Article frome a thesis

a. کرمی خانیکی ¹ , f. بخشنده ² , k. لاری ³

1 - عضو هیات علمی پژوهشکده حفاظت خاک و آبخیزداری
2 - دانش آموخته‌ی فیزیک دریا
3 - عضو هیات علمی دانشگاه آزا د اسلامی واحد تهران شمال

Received: 2014-09-13 Accepted : 2014-09-13 Published : 2014-08-23

Keywords: Ebb shoal, flow shoal, inlet, MIKE21, sediment transport, tidal current,

Abstract :

The current and sediment transport patterns are important factors affecting coastline morphology. Subsequently, these factors are influenced by waves and currents. Currents are generated by waves breaking on the coastal area. A simultaneous presence of a long shore and tidal currents makes the inlet. A complex hydrodynamic area. The effects of tidal currents on sediment transport pattern and sedimentary features of inlets were studied by numerical modeling. The junction of a small bay to an open sea was modeled using the MIKE21 software. Different conditions of tide amplitudes (0.5, 1.5, 2.5 meters) were investigated. The results clearly indicated the formation of two vortexes during transformation from flow to ebb tide and vice versa. These vortexes, in association with the tidal flow and ebb currents, produce some shallow areas at the sides of the inlet. The radius of the tidal vortexes, and the width of sedimentation area, are directly dependent on the tide amplitude. Using an analysis of Keulegan, when tide amplitudes were 1.5 and 2.5 meters, there was flow dominance in sediment transport capability (i.e.  net bay-ward transport).when the tide amplitude was 0.5 meter, there was the ebb dominance of sediment transport capability.