Discharge Characteristics of Conduit Radial Gate

The discharge characteristics of the conduit radial gate are still not well-known worldwide from the limited research done. Generally speaking, the values of discharge coefficient vary from 0.50 to 0.75 for the radial gate. The gate lip geometry has a major influence on the discharge coefficient for flow under the gate, the dimension of the conduit, the gate opening and the pressure head also influence the discharge coefficient. The study analysed the available experimental data, the factors influencing the discharge coefficient were determined. The scaled model experimental data were adjusted using the scale effect factor, c, which is a function of Reynold Number. A set of relational expressions were derived from the experimental data series, and evaluated mathematically by using the R- squared value which is a co-relational factor to describe the fitness of the mathematical equations to represent the data series.The derived formula / charts were calibrated using the field data of 1998, 1999 and 2000 year flood releases through the emergency spillway of Pongolapoort dam. Satisfactory verification results were achieved.