Assessing the impact of velocity dip and wake coefficients on velocity prediction for open channel flows

The aim of the present study is to assess the impact of the velocity-dip and wake strength on the velocity prediction using the dip modified laws. The dip modified laws, particularly the dip modified log wake law (DMLW-law), are preferred over the traditional wall laws in the narrow open channels. This is mainly because these analytical-based laws basically rely on parameters for the velocity dip (α) caused by secondary flow and for the wake strength (Π) due to the turbulence and boundary walls. In this study, comprehensive expressions for estimating these two key parameters were proposed and tested for smooth and rough flows. The results indicated that the proposed expressions can noticeably improve the application of the DMLW-law model to both smooth and rough flow