Study of the infl uence of forced fl uid oscillations on the hydraulic resistance of a pipeline

Source abstract

This article addresses the problem of reducing hydraulic resistance. Since early studies of the relation between the applied pressure difference at the ends of a pipeline and the fluid flow rate in it, researchers have been concerned with determining the energy losses of a fluid during its motion. Faced with the turbulence - understanding the laws and principles of motion of individual fluid particles and determining hydraulic resistance during turbulent fluid flow - researchers have put forward several theories describing the laws of motion. Solving these tasks for a stationary state led to a new problem - reducing hydraulic resistance during turbulent flow. Based on the theory of the relative displacement of fluid particles, established by the founders of turbulent flow research, and works on the analogy between energy and fluid motion, the authors hypothesize the possibility of controlling hydraulic resistance using an energy source - a pump supplying fluid to the pipeline at a certain frequency. The article presents the results of a study of fluid flow in a pipeline with a variable flow rate, i.e., the movement of fluid under the periodic action of a pump. A model is presented that describes the pressure at the starting point of a pipeline and the fluid flow rate based on an electrohydraulic analogy, in which frictional energy losses are expressed through a complex quantity reflecting the action of the viscous, inertial, and elastic forces of the fluid. As our measurements have shown, the complex hydraulic resistance, which consumes energy during fluid flow through a pipeline, underlies the determination of the attenuation coefficient of a propagating pressure wave, suggesting an analogy between wave propagation and the turbulent movement of fluid through a pipeline.