Steady flows and unsteady ones in pipes: models link and quasistationarity hypothesis

摘要

Models of unsteady flows and stationary ones in pipes and the requirements of their joining are considered. In this view, the problem of the description of a friction at a non-stationary flow is considered. So-called “quasi-stationarity hypothesis” is discussed. The formula for a friction coefficient generalized on a non-stationary case is offered. It is concluded that additional losses at the non-stationary mode are caused by energy consumptions for reorganization of speed chart.