| Abstract |
| This hydraulic model experiment analyzed plunge pool of downstream and sulfur change of downstream depending on discharge flow in order to produce the optimal design plan of auxiliary spillway to be established. To that end, hydraulic characteristics of existing spillway were examined and hydraulic model experiment was conducted on design 1 and 2. First, the results of design 1 show that discharge ability is fine, approach velocity is within limits, but there is a need for improvement through a baffle wall shape change as a whirlpool occurs because of a baffle wall. In the case of sulfur of downstream water flow discharged from steep spillway is not sufficiently reduced and flows into downstream in super-critical flow condition. And as for PMF, near the spilling basin of the existing spillway and spilling basin of auxiliary spillway, unstable phenomena and whirlpool of water surface partially occur, but when considering that water level change is not significant at measuring points in the cross section of downstream as the main flow direction is concentrating into the center of downstream, the danger regarding downstream is limited as found in the analysis. Lastly, the analysis found that the factors risking original functions and safety of spillway structure occurring in the design 1 do not occur in the design 2, and show stable flow characteristics compared with the design 1. Therefore, detailed data regarding size and form of plunge pool and distribution characteristics of flow going into downstream are secured additionally through experiments, they will serve as very useful basic data for designing auxiliary spillway of similar dams. |
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| Key Words |
| Auxiliary spillway, Plunge pool of downstream, Sulfur change of downstream |
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