Equation used in Wave Speed Calculator tool

  Product(s): HAMMER
  Version(s): CONNECT Edition, V8i
  Area: Calculations

Problem

What equation does HAMMER use to calculate Wave Speed in the Wave Speed Calculator Tool?

Solution

HAMMER uses the following equation developed by Korteweg. This is generally considered valid for thin-walled pipelines (D/e > 40) so if your pipe is not thin-walled (for example HDPE pipes may be too thick) or if you do not want to use the Korteweg equation, use another method such as ModelBuilder import as described here: Entering Pipe Wave Speed for a Transient Simulation

For more information, see page 586 of Advanced Water Distribution Modeling and Management.

Where:

a = Wave speed (ft/s, m/s)
Ev = Bulk modulus of Elasticity (lbf/ft^2, Pa)
p = liquid density (slugs/ft^3, kg/m^3)
D = Diameter (in, mm)
e = wall thickness (in, mm)
E = Young's Modulus (lbf/ft^2 / Pa)
ψ = pipeline support factor (see below)

  • Pipe is anchored throughout against axial movement: ψ = 1 - µ 2 , where µ is Poisson's ratio
  • Pipe is equipped with functioning expansion joints throughout: ψ = 1 - µ/2
  • Pipe is supported only at one end and allowed to undergo stress and strain both laterally and longitudinally: ψ = 5/4 - µ (ASCE, 1975)

See Also

Advanced Water Distribution Modeling and Management.

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