Unified Approach for Damping Rate of Transient Laminar Flow: Experiments, Computational Fluid Dynamics, and One-Dimensional, and Global Models

Abstract Pipe networks exhibit complex geometries and are equipped with electromechanical devices capable of generating hydraulic transients. Most of these devices are remotely controlled and managed through an integrated system that prioritises network demands. This implies that potential hazardous pressure peaks, that may occur during each operation, may need to be taken into account. Consequently, when multiple operations take place in a short time interval, transient pressure waves, generated in different parts of the network and travelling back and forward, overlap and can be larger than the design maximum pressure. To address this concern, it is essential to evaluate the pressure damping rate of critical maneuvers and to identify a "safe" time interval between maneuvers to prevent the risk of inappropriate pressure waves overlapping. With the aim of analysing the damping rate of closure maneuvers, both numerical and laboratory experiments have been executed for a laminar flow in a reservoir-pipe-valve system. In this context, a three-dimensional Computational Fluid Dynamics, a one-dimensional and global model, the latter based on a sinusoidal function, have been used. Guidelines are then presented for identifying the safe time interval between maneuvers.