Laboratory study of stilling basin using trapezoidal bed elements

Abstract

When designing dam spillway structures, the most significant consideration is the energy dissipation arrangements. Different varieties of baffle blocks and stilling basins have been used in this context. However, the hydraulic jump form of stilling basin is considered to be the most suitable. The main objective of this research was to introduce four different baffle block shapes (models arranged from A to D, installed at slopes 0.00, 0.04, 0.06 and 0.08 in the stilling basins). To illustrate the consequences for the qualities of pressure-driven bounce, each model was attempted in the bowl. The trials applied Froude numbers between 6.5 and 9.2. The puzzle square model D provided the best outcomes compared to the models A, B, C and smooth. Model D with different models at inclines 0.00, 0.04, 0.06 and 0.08 was used to consider the impacts of perplex hinders on water driven-bounce when bed slants were changed. When the model D baffle used instead of a smooth bed at 0.08 slope, the reduction in y2 / y1 reached 12.8%, and Lj / y1 was 18.9%. Among the different bed slopes, a normal decrease in y2 / y1 ranged from approximately 10.3%, whereas the normal decrease in Lj / y1 was about 13.8% when the model D baffle was used instead of the model A baffle with a horizontal slope bed of 0.00. The results show that the new shapes led to a decrease in sequent profundity proportion and length of jump proportion; however, the energy dissipation proportion increased.