الفهرس 
Chapter (7) Compound TransitionsOnly 14 pages are availabe for public view
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Abstract
The study of open-channel transitions is an important aspect in hydraulic engineering. Transitions in the flow depend on the discharge, boundary geometry and state of flow. They may be horizontal, vertical or compound for the same cross section. The analysis of transitions is aided by the use of flow depth and velocity head terms in the energy equation. The sum of the two terms is called the specific energy.In the present work, the compound transitions for rectangular section are highlighted. Experimental results of the present study are presented in the form of tables, curves and statistical equations. from the analysis of results. Dimensionless relationships based on this experimental work may be used for design purposes and they may provide more accurate solution than the theoretical one. Using SPSS program, statistical equations were derived giving the characteristics of flow in the compound transition section for discharge values varied between 2.5 and 16 L/s, values of ΔZ/L were 0.025, 0.05, and 0.075, and Δb/B were 0.17, 0.33, and 0.5.The velocity profiles were developed from the experimental study. The positions of the mean water velocity as well as the maximum velocity depend on discharge, contraction ratio, and size of hump. The maximum and mean values of velocity occur nearer to the water surface in the upstream than the transition section.Kinetic energy (α) and momentum correction coefficients (β), were computed for 9 different models by using two methods. The first one was based on the calculation of ε where ε = ; in which u is the velocity, and the second method was based on dividing the cross section into slides and using the corresponding velocity for each slide. The results of the present study showed that the second one was more accurate than the first method. The average values of α (energy coefficient) and β (momentum coefficient) at the transition section were 1.237 and 1.10, respectively. The values of (α-1/β-1) ranged from 2.71 to 2.81, this range did not exceed 4% for different Reynolds number which varied between 2145and 14390.This research work presents the turbulence intensity (TI), Reynolds shear stress (Res), and turbulent kinetic energy (TKE) for different values of discharge through compound transition models.The turbulent intensity (TI) decreased with the decreasing value of discharge. TI in the transition section was less than the corresponding ones in upstream section. Also, the maximum values of TI occurred either close to free surface or close to bottom. The effect of Reynolds stresses was studied for all used values of discharge, It was found that the Reynolds shear stress in the horizontal plane ρu’v’ had a much greater magnitude than the other two planes ρu’w’ and ρv’w’. Turbulent kinetic energy (TKE) per unit mass for used discharge values had bigger values in the upstream section than the corresponding ones in the transition section.