02 · Basic concepts

Network elements

• Node: connection point; may have demand and elevation.
• Pipe: links nodes; needs length, diameter, and roughness.
• Tank/Reservoir: source or storage; defines water level.
• Pump: adds energy; its curve defines pressure gain.
• Valves (PRV/PSV/FCV): regulate pressure or flow depending on type.

Key quantities

• Demand: requested flow at a node (L/s or m³/s).
• Elevation: node height; affects available energy.
• Pressure: usable energy at the service point; low pressure means poor service.
• Friction loss: energy dissipated while flowing; increases with velocity and roughness.

Hydraulic simulation

• Computes pressures and flows that balance demands and boundary conditions.
• Uses loss models (Hazen-Williams or Darcy) and numerical solvers.

Quick mental example

• If a pump stops, downstream pressures drop; increasing a critical pipe diameter reduces loss and raises nearby pressures.