Concept Of Critical Shear Stress In Loose Boundary Open Channels

The problem of defining critical flow condition associated with the initial instability of bed material particle has been studied in relation to existing concepts. The data has been collected and analysed to indicate that a distinct condition for the beginning of movement doe not exist. The bed load transport in the proximity of so called critical shear stress is governed by certain well defined law. For all practical purpose, a limiting bed shear stress for a bed material can be defined below which the bed load transport is of no practical importance.