theoretical research, friction factor, hydraulically rough pipes, region of pre-quadratic turbulence, dimensional analysis method
Abstract
The study presents the results of a comprehensive theoretical and analytical investigation of the friction factor in pipes with a uniformly rough internal surface. Based on the principles of dimensional analysis, a detailed mathematical model was developed to determine the friction factor within the pre-quadratic zone of turbulence, where the flow regime transitions between smooth and fully rough conditions. The proposed model accounts for the influence of relative roughness, Reynolds number, and flow structure parameters, enabling a more accurate description of hydraulic resistance under turbulent flow. To validate the theoretical findings, the classical experimental data obtained by J. Nikuradse for pipes with uniform roughness were subjected to modern statistical processing and comparative evaluation. Furthermore, a conceptual physical model was introduced to describe the dynamic interaction of vortices in the boundary layer formed above the rough pipe surface. The results contribute to a deeper understanding of turbulence mechanisms and provide a basis for improving the prediction of energy losses in hydraulic systems with rough-walled conduits.
Author Biographies
I. E. Dovbenko, National University of Water and Environmental Engineering, Rivne
PhD student
V.A. Voloshchuk, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”
