| Abstract: | An investigation of the flow at a rough surface, as well as in pipes and channels with rough walls, is one of the most important problems of applied hydrodynamics. Results of classical investigations, in which the most important flow properties near a rough surface are clarified, are generalized in [1–3]. These investigations are the basis for the construction of numerous semiempirical theories using the “mixing path∝ model of L. Prandtl (for instance, [4–6]). However, despite their simplicity these methods possess all the disadvantages inherent in the Prandtl theory: They are not universal, they describe the transition from the laminar to the turbulent mode poorly, and they are not applicable for the computation of complex non-self-similar flows. Meanwhile, an analysis of the experimental results obtained in [7], for example, indicates an extremely complex flow structure both in the neighborhood of the rough surface and far away from it. Models using the differential equation of the kinetic energy of turbulence have recently been developed to describe turbulent flow near a rough surface [8]. The possibilities of applying a model using the equation for turbulent viscosity to close the problem [9] are analyzed in this paper in an example of a steady turbulent incompressible fluid flow in a circular pipe with rough walls. |
