Effects of Cut-Off (Flood Relief) Channel Intersection on Bend Flow Characteristics

Civil engineering, Hydrologic sciences

Fares, Youssef Ramsis

University:University of Glasgow

关键词: Civil engineering, Hydrologic sciences;   

Others  :  http://theses.gla.ac.uk/77961/1/10999279.pdf

来源: University of Glasgow

【 摘 要 】

The characteristics of flow in a gentle wide channel bend at the intersection with a cut-off (flood relief) channel are studied. The studies are restricted to subcritical flows in bends with rigid boundaries and uniform rectangular cross sections. The object is to demonstrate how the intersection affects the water surface and velocities profiles in the channel bend. Two approaches are employed in the study namely; + Mathematical Approach + Experimental Approach The mathematical approach is divided into two stages. The first stage is concerned with the formulation of the flow in a gentle wide channel bend and the second stage with the formulation of the flow at the intersection with the flood channel. The flow entering the flood channel is treated as the flow spilling over a side weir with a broad crest. The conventional equations of motion are used to establish the model equations which are then solved numerically using a finite difference technique. For the experimental approach, a laboratory model was constructed in order to obtain physical data principally for the verification of the mathematical model. The analysis of the results follows two distinct lines: + Quantitative Analysis: where comparisons between the theoretical and experimental profiles are made for the bend flow with and without the introduction of the flood channel intersection. Principally for verification of the mathematical model results. + Qualitative Analysis: where qualitative comparisons between the flow profiles in both cases are made in order to show the influence of the intersection on the bend flow characteristics. The analysis shows that the suggested mathematical model can be used satisfactorily for high to medium flood channel bed levels. It is further shown that the bend characteristics continue to dominate the flow again for high to medium (weir) flood channel bed levels but that at medium to low (weir) channel bed levels, the local effects produced by the intersection predominate.