An approximate analytic solution of uniform laminar flow in a circular open channel

An approximate analytic solution of the Navier-Stokes equations for laminar flow in a circular open channel is presented. The solution is valid for the case of incompressible steady uniform flow in a low-filled channel. (The depth ratio, which is flow depth divided by channel radius, is smaller than one.) The solution is compared with a recently reported exact theoretical solution and found to be in reasonably good agreement. Expressions for variation of the correction factors for momentum and kinetic energy fluxes with flow depth are presented. A correlation between the momentum and kinetic energy flux correction factors is proposed and compared with data reported in the literature.