Transient Pressure Acoustics Model
The Transient Pressure Acoustics Model node adds the equations for primarily time-dependent (transient) acoustics modeling. This is the scalar wave equation
where pt is the total acoustic pressure, ρ is the fluid density, c is the speed of sound, qd is the Dipole Domain Source, and Qm is the Monopole Domain Source. In this formulation of the wave equation the speed of sound and density may in general be space dependent but only slowly varying in time, that is, at a time scale much slower than the variations in the acoustic signal.
In the Settings window, define the properties for the acoustics model and model inputs including temperature.
Transient Pressure Acoustics Model
See Pressure Acoustics for details of the fluid model equations.
Select a Fluid model: Linear elastic (the default), Viscous, Thermally conducting, Thermally conducting or viscous, or Ideal Gas. Then see the descriptions for The Pressure Acoustics, Frequency Domain Interface:
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Defining a Linear Elastic Fluid Model
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Defining a Viscous Fluid Model
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Defining a Thermally Conducting Fluid Model
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Defining a Thermally Conducting and Viscous Fluid Model
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Defining an Ideal Gas Fluid Model
Model Inputs (Ideal Gas Only)
If Ideal gas is selected as the Fluid model, enter a Temperature T (which can be a constant temperature or a temperature field from a Heat Transfer interface) and an Absolute pressure pA:
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Select User defined to enter a value or an expression for the absolute pressure (SI unit: Pa) in the field that appears. This input is always available.
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In addition, select an absolute pressure defined by a Fluid Flow interface present in the model (if any). For example, select Absolute pressure (spf) to use the absolute pressure defined by a Laminar Flow interface spf. This allows the use of a system-based (gauge) pressure, while automatically including the reference pressure in the absolute pressure.