Free Web Tool

Water Hammer Surge

Joukowsky surge head and pressure for sudden valve closure with slow-closure (Michaud) check based on closure time vs 2L/a.

Inputs

Velocity V (m/s)

Pipe Material

Wave speed a (m/s)

Pipe Length L (m)

Closure time tc (s)

Static head H₀ (m)

γ_water (kN/m³)

Method — Joukowsky

Critical (instant) closure: ΔH = a·V/g.
If tc > 2L/a, closure is “slow”: ΔH ≈ 2·L·V/(g·tc).
Surge pressure: ΔP = ρ·a·V (Pa). Total max head = H₀ + ΔH.

Results

2L/a (critical time)—

Closure type—

Joukowsky ΔH—

Slow closure ΔH—

Surge ΔP—

Max total head—