Effect of Turbulence Intensity on Riprap Stability over Streambeds

Abstract

The effect of turbulence intensity on riprap stability was studied experimentally. Riprap stones were placed on a flat streambed and turbulence intensity was changed with a turbulence generator. An acoustic Doppler velocimeter (ADV) was used to measure turbulence intensity. Results showed that in a constant flow condition, by increasing the near-bed turbulence intensity from 10% to 25%, the stable riprap diameter increased about 2.5 times. Based on the results of the present work and using all existing data, an empirical equation was developed for calculating stable riprap stone size considering the time averaged near-bed velocity and near-bed turbulence intensity.