دانلود کتاب مدلسازی هیدرولوژیکی هیدرولیک، منابع آب و مهندسی سواحل

Flow from the pipe outlets under a high head of water emerges in the form of a straight, concentrated shooting jet.Hydraulic structures called stilling basins have to be provided for reducing the energy of high-velocity flow to prevent erosion of the natural bed downstream and banks of river or cannel so that the flow beyond the basin does not endanger the stability of bed and banks of the downstream channel. The experimental investigation leading to the development of a new stilling basin model design for a non-circular pipe outlet using a triangular splitter block along with USBR VI impact wall and sloping end sill is reported in this paper. On the basis of the present study, the new stilling basin design has been compared with USBR VI stilling basin. The main aim of this research paper is to present an experimental study for the purpose of improving the performance of the USBR VI stilling basin for a non-circular pipe outlet by developing new physical models in the laboratory. The new models were tested in a rectangular-shaped pipe outlet of size 10.8 cm × 6.3 cm, for the Froude numbers, namely Fr = 1.85, 2.85 and3.85 in comparison to USBR VI stilling basin model recommended for the pipe outlets. The new models have been developed by putting the triangular splitter block while keeping the other configuration of stilling basin geometry the same as suggested by the USBR VI stilling basin. The scour pattern was measured for each test run. The performance of the basin was compared by performance index (PI). After twelve test runs, it is found that, for a given Froude number range, by inserting the triangular splitter block with the same impact wall along with the end sill, the performance of stilling basin is improved, and also the length of the newly developed basin is reduced to 29% as compared to USBR VI stilling basin for given flow conditions.