Numerical study of energy dissipation and block barriers in stepped spillways

In this research, the accuracy of the Flow-3D numerical model in the flow simulation in a stepped spillway was probed using data obtained from the physical model. In addition, the effects of block barriers on the energy dissipation rate were investigated. To adopt a proper turbulent model, Renormalization Group k-epsilon, RNG k-epsilon, and standard k-epsilon models were employed. Then, the Flow-3D was run in five discharges for nine spillways with the ratios of block length to step length (L-b/l) and block height to step height (H-b/h) as 0.3, 0.4, and 0.5. The results indicated that both turbulent models had almost similar outcomes though the run time of the RNG k-epsilon model was shorter. The blocks with a shorter length in low ratios of H-b/h and the lengthier blocks in high ratios of H-b/h undergo more relative energy dissipation relative to the no-block situation. For H-b/h = 0.3 and L-b/l equal to 0.3, 0.4, and 0.5, the relative energy dissipation climbed on average as 8.5, 6.5, and 4.5% respectively, compared with the no-block case. The most influence exerted on relative energy dissipation was obtained via the blocks with H-b/h = L-b/l equal to 0.3 and 0.5 with respective increases of 8.6 and 8.4%.