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Flow in Pipes: Systems & Networks - Theory & Concepts - Water Hammer

Series, parallel and branching pipes, resistance formulations, equivalent systems, three-reservoir problems, Hardy Cross and nodal-head network methods, pumps, valves, demands, and hydraulic transients.

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Water Hammer Simulator

Elastic-pipe wave speed and rapid/slow valve-closure pressure rise.

Zero represents an ideal instantaneous closure.

Wave celerity (cc)1343 m/s
Critical closure time (Tc=2L/cT_c=2L/c)0.149 s
Closure classificationRapid
Maximum pressure rise (Δp\Delta p)2.69 MPa
Equivalent head rise (ΔH\Delta H)273.8 m
ReservoirValveL = 100 mt = 0.000 sΔp = 2.69 MPa
Normal flowCompression waveReflected low-pressure phase

Rapid closure uses the Joukowsky relationΔp=ρcΔV\Delta p=\rho c\Delta V. For closure slower thanTc=2L/cT_c=2L/c, this educational model uses the classical gradual-closure approximationΔp2ρLΔV/T\Delta p\approx2\rho L\Delta V/T. Real systems may require method-of-characteristics analysis including friction, valve law, pipe restraint, entrained air, and vapor-column separation.