Practical Approximate Turbulent Boundary Layer Calculation into the Divergent Rectangular Channel

Abstract

Both plane and axially symmetrical turbulent boundary layers are analysed in the sense of the well‐known phenomenologic semi‐empiric boundary‐layer theory. The analysis is based on an analogy with the rheologic power‐laws widely used in the study of non‐linear viscous flows. A simple “one layer method” to calculate both plane and axisymmetric turbulent boundary layers is first derived and after that tested on the model of a rectangular channel, used for the hydraulic machines for instance. The model is composed of an annular disc and two perpendicular radial plates in the flow produced by a linear source. Neglecting the interaction between the disc and two plates, both boundary layers are considered separately: the plane boundary layer between two divergent plates and the axially symmetrical boundary layer on the disc (even in the presence of a funnel above the disc to vary the slowing down of the flow).