Applicability analysis of representation forms for hydraulic coefficients and transient parameters of unsteady pressurized fluid flows

A general solution is considered of a number of problems for an unsteady laminar liquid flow in a round tube at a sudden change in the pressure gradient. A comparison analysis of obtained results and data on experimental studies of aperiodic and periodic turbulent liquid flows in a round horizontal tube in a stabilized section is presented. Basing on the performed analysis flow regions have been revealed in which it is difficult to use universally adopted techniques for processing and presenting data on the main flow characteristics: friction and resistance coefficients, and nonstationarity parameters. It has been concluded that the main difficulty arising in the process of processing and presenting data on the study of unsteady forced flows lies in the presence of a range of measurement of a flow average velocity near zero where main parameters characterizing the flow suffer a discontinuity