Prediction of Flow Velocity Near Inclined Surfaces with Varying Roughness

摘要

Velocity at the toe of structures, such as spillways, drops, and chutes, plays an important role in designing protective and control hydraulic structures. In this study, laboratory experiments were conducted to investigate velocity at an inclined surface with a height of 40 cm made up of galvanized steel in a flume 20 m long and 0.6 m wide. Using three different slopes, five different discharges and five kinds of roughness, 75 experiments were done. Comparison of measured and theoretical (measured by energy equation without considering losses) flow velocities showed that over the inclined bed, the correction coefficient of theoretical velocity for different Froude numbers varied from 0.87 to 0.88, reducing with roughness size. Roughness size, Froude number and the ratio of water head to the length of bed play a dominant role in the prediction of velocity.