When is hydraulic transient analysis required and what methods are used?

Transient analysis required for: long pipelines (surge travel time significant), pump trip scenarios, rapid valve operations, and check valve slam assessment. Methods: method of characteristics (MOC) - converts PDEs to ODEs along characteristic lines, most common for pipeline surge; wave plan analysis - graphical for simple systems; finite element methods - for complex systems. Analysis determines: maximum/minimum pressures, surge equipment sizing (relief valves, surge tanks, vacuum breakers), and valve closure time requirements. Software includes AFT Impulse, Pipenet, and HAMMER.