An experimental study of baffle blocks as flow energy dissipation in the launch channel of a spillway structure

Abstract

Energy dissipation in a launch channel focused on increasing the dissipation of initial water flow energy to protect against hydraulic structure failure. This was achieved by using rectangular baffle blocks placed within the launch channel, varying in angles and flow rates. The aim of this study was to determine the impact of different angles of the rectangular baffle blocks on flow energy dissipation downstream of a spillway structure. A two-dimensional experimental research method was employed to assess the water energy dissipation by varying the angles of the baffle blocks in the launch channel. The results of this study indicated that in the rectangular baffle block type with an angle variation of 300, the relative energy dissipation was directly proportional to the upstream and sequential Froude numbers. In contrast, for the baffle blocks with an 1800 angle variation, the relative total energy dissipation decreased as the upstream and sequential Froude numbers increased. The maximum value of the relative total energy dissipation occurred when the water level above the crest was high, but the minimum value happened when the water level above the crest was low. One key finding of this study was that the rectangular baffle blocks with a 300-angle variation and a relative water surface height of 2.5 cm above the crest provided a maximum total relative energy dissipation of 53.66%. The advantage of using rectangular baffle blocks was in their ability to gradually slow down the flow velocity through the gaps between the angled blocks, preventing the formation of back momentum in the flow.