A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering

Thesis (M.Eng.) - Asian Institute of Technology, 1989

Cavitation erosion occurring on the surface of the hydraulic structure is ca used by the surface irregularities, subjected to high velocity and high head flow down the channel, the cavitation damage is prone to happen. To prevent this damage, the installation of aeration device on the spillway channel has been proven to be successful and economical. In the present study, experiments have been carried out on two models of steep slope rectangular spillway channel with vertically constant radius curved profile in downstream. The investigation of the effective length has been performed on these two models with some ae ration devices having various shape parameters of square groove with deflector type and different flow conditions. The results obtained from this study can be used as a reference to deter mine the effective length between aeration grooves on the curvature spillway channel with the groove installed at the tangential point. Due to the radius of curvature spillway channel is constant the results obtained from this study can be utilized conditionally. An attempt is also made to investigate the sensitivity of the ratio of the effective length to the water depth resulted from shifting the location of aeration groove 50 cm up stream of the tangential point. It is found that there is no relevant relationship between the ratio of the effective length to the water depth and relating parameters.