Removal efficiency of sediment by self-cleaning of combined rectangular weir with three ectangular bottom openings by using ANN

الملخص EN

This research was based on laboratory experiments for obtaining the sediment removal efficiency for a rectangular weir with three rectangular bottom openings.

Thirty-three physical models were made for weir without openings, weir with one opening, weir with three openings, for purpose of comparison.

These models were operated under clear-water condition and by using the uniform cohesion less sand as bed material.

Dimensional analysis was made to relate the maximum scour depth, width and length of the scour holes created at the upstream and downstream sides of the weir, with different geometrical and flow variables for each flow case.

The SMS Software-RMA2 Model was used to obtain the velocity distribution to be related to the simulation of the self-cleaning efficiency for the proposed weir models.

The coefficients of variation for the estimated removal efficiency of sediments at both sides were (1.113-0.465), which indicate the necessity of obtaining a model to describe this variation.

Experimental data analysis had shown the flow conditions such as the head difference ,the head over the weir, time, dimensions of openings, number of openings have considerable effect on the scour holes volume at both sides of the weir.

ANN models were developed herein using the (SPSS software, version 19) to express the removal efficiencies of sediment both at the upstream and downstream sides of the weir as a function of the different geometrical and flow variables.

These obtained ANN models were found to have correlation coefficients range (r = 0.989-0.803) between the observed and predicted removal efficiencies.

These high correlations indicate the capability of these models for a very good predictions.

These models were used in a Visual Stuido Net, 2010 program in order to be used by engineers to find the removal efficiency of such structure.