Open AccessThe Effect of Inception Point on Dissipation Energy in Stepped Spillways Modeling
Author(s) -
Denik Sri Krisnayanti,
Suhardjono,
Very Dermawan,
Djoko Legono
Publication year - 2019
Publication title -
xi'nan jiaotong daxue xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.308
H-Index - 21
ISSN - 0258-2724
DOI - 10.35741/issn.0258-2724.54.3.3
Subject(s) - spillway , froude number , dissipation , mechanics , air entrainment , flow (mathematics) , energy (signal processing) , geotechnical engineering , engineering , mathematics , physics , statistics , thermodynamics
Stepped spillway is generally a modification on the downstream face of a standard ogee spillway. The steps increase significantly the rate of energy dissipation taking place along the chute and reduce the size of the need for a large energy dissipate at the toe of the spillway. In skimming flow conditions, the steps act as roughness factor which is great because most of the energy is lost to maintain horizontal vortices that develop beneath the pseudo bottom. This study aimed to investigate the effect of the inception point against the value of the relative energy loss on the stepped spillway in skimming flow regime. In this research, the models test of stepped spillway carried out with twelve configuration and variations of ratio (dc/h). The slope of stepped spillway (θ) is used 30˚ and 45˚, the number of steps (N) are 40 and 20, and two type of steps: flat steps and pooled steps. The critical depth to the height of steps (dc/h) is ranging from 0.700 < dc/h < 3.00 with the discharge per unit width 69.13 cm2/s < q < 707.65 cm2/s. The results showed that the relative energy loss can be analyzed to be a function of the inception points, the number of steps, and the slope of spillway, in the equation form of (ΔH/Hmax) = a (Li/ks)bNc(sin θ)d. The discharge which function of the Froude number and height of the step already include to the length of inception point parameters.