Pipe Properties
The Pipe Properties node is used to define the pipe shape, pipe model, wall drag force, and flow profile correction factor.
Pipe Shape
Select a pipe shape from the list—Not set (the default), Circular, Square, Rectangular, or User defined.
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For Circular enter a value or expression for the Inner diameter di (SI unit: m). The default is 10 cm (0.01 m).
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For Square enter a value or expression for the Inner width wi (SI unit: m). The default is 5 cm (0.005 m).
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For Rectangular enter a value or expression for the Inner width wi (SI unit: m; the default is 5 cm) and Inner height hi (SI unit: m; the default is 10 cm).
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For User defined enter a value or expression for the Cross sectional area A (SI unit: m2; the default is 0.01 m2) and Wetted perimeter Z (SI unit: m; the default is 0.4 m).
Pipe Model
Select a Pipe model—Incompressible cross section (the default), Zero axial stress, Anchored at one end, or Anchored at both ends.
When Zero axial stress, Anchored at one end, or Anchored at both ends is chosen, select an option from the Young’s modulus E (SI unit: Pa) and Wall thickness w lists—Not set (the default) or User defined. For User defined in either case, enter different values or expressions.
For Anchored at one end or Anchored at both ends also select an option from the Poisson’s ratio v (dimensionless) list—Not set (the default) or User defined. For User defined enter a value or expression.
Wall Drag Force
Enter a value or expression for τw (SI unit: N/m2). The default is 0 N/m2.
Flow profile correction factor
Enter a value or expression for β (dimensionless). The default is 1. For most practical applications this correction factor is 1 as the propagating waves are assumed plane and uniform. This value should typically be changed if a wall drag force is introduces or if a non-plug-flow background flow field is used. The flow profile correction factor is defined as
where the velocity field is the actual one that exists in the pipe cross section. The factor thus measures the deviation from a flat background flow profile (plug flow) and a plane propagating acoustic wave.
Flow Profile Correction Factor β