Parameter · 05 Boundary Conditions

Incident power

acoustic_port.power_W Unit: W Step 05 · Boundary Conditions

The sound power of the plane wave entering the model through this inlet (input = power). The program converts it into an amplitude using the port area and the density and sound speed of the port's gas.

Last updated 2026-11-03

Theory

Equal powers at two inlets of different areas (or temperatures) correspond to different amplitudes. Power is the natural input when the sound power of the source at each inlet is known. The amplitude follows from equation (1); everything else is as for an entered amplitude (Incident amplitude).

Equations

|A| = \sqrt{\frac{2\rho c\,W_{in}}{S}}

(1)

where	meaning	unit
$W_{in}$	Incident power (this field)	W
$A$	Resulting incident amplitude	Pa
$S$	Port area	m²
$\rho, c$	Density and speed of sound at the port	kg/m³, m/s

Default and rule

Default: 1 W
Rule: 1 W.
Source: The plane-wave power in a duct without flow is the standard result for a uniform medium.

Valid range > 0

Values

Above 0. Only the ratios between inlets matter for the transmission loss.

Theory

Equations

Default and rule

Valid range > 0

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