Water Velocity, Vorticity and Bed Deviation Modeling for a Reach from Damietta Branch Using K-ε Turbulence Model Solved by Cubic Interpolated Pseudo (CIP) Method

Abstract

A multi-meander reach with length of 20 km located between km 130.0 and km 150.0 downstream of Delta barrages - Damietta branch was selected and numerically studied. This study aimed to simulate and study numerically the water velocity, vorticity and bed deviation of the curved zones for the reach under study and illustrating the relationship between them. Consequently, the vulnerable zones subjected to maximum velocities were accurately determined. Field data were collected and analyzed for the modeling process. A 3-D model called iRIC (International River Interface Corporative) based on an explicit finite difference method (Abbott-Ionescu scheme) was applied. Therefore, in order to fulfill such objective, standard K-ɛ turbulence model was employed using Cubic Interpolated Pseudo (CIP) method for solving the advection terms. For illustrating obviously the variation of water velocity with vorticity and deviation of bed elevation, two important zones consisted of several meanders were selected, the first zone located from km: 132.00 to km: 137.33 while the second located between km: 137.33 and km: 142.67. Through the modeling process, it was assumed that the sediment particles move in the bed layer zone only. From this study, it was found that for both selected zones, the velocity value was ranged between 0.13 m/sec and 0.24 m/sec, and it could be considered as a small range to make scouring process. It was observed also, that there was a noticeable relationship between water velocity, vorticity and deviation of bed elevation.