Periodic Head-Flow Elements

The Periodic Head-Flow element represents a versatile hydraulic boundary condition which allows you to specify a constant head (pressure), flow, or any time-dependent variation, including periodic changes that repeat indefinitely until the end of the simulation.

Note: The Periodic Head/Flow element supports a single branch connection only. If there is more than one branch connected to it, the transient run will fail and an error message may appear, such as: "Only one active pipe may be connected to this type of node in its current configuration."

This element is used to prescribe a boundary condition at a hydraulic element where flow can either enter or leave the system as a function of time. It can be defined either in terms of Head (for example, the water level of a clear well or process tank) or Flow (for example, a time-varying industrial demand). The periodic nature of variation of head/flow can be of sinusoidal or of any other shape that can be approximated as a series of straight lines.

Note: During a Steady State of EPS run (used to determine the initial conditions for a transient analysis), the head/flow for this element is held constant at the initial head/flow value on the sinusoidal or user-defined pattern. The head/flow only varies during a transient analysis.