Circular Piston Radiation Impedance

R2026b

Radiation impedance of circular piston with an infinite baffle

Since R2026b

• 

Circular Piston Radiation Impedance block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Simscape Acoustics / Radiation Impedance

Description

Add-On Required: This feature requires the Simscape Acoustics add-on.

The Circular Piston Radiation Impedance block models the radiation impedance of a baffled piston. It assumes that the piston is mounted on an infinite baffle where the front and rear side do not interfere with each other.

The block models the equivalent circuit [1] shown in the figure using the equations

$$\begin{array}{l}M=\frac{8\rho }{3{\pi }^{2}r}\\ C=\frac{1.89\pi r^3}{\rho c^2}\\ R_1=\frac{0.1404\rho c}{r^2}\\ R_2=\frac{\rho c}{\pi r^2},\end{array}$$

where:

• M is the inertance value of the Acoustic Inertance block.

• C is the compliance value of the Acoustic Compliance block.

• R₁ is the resistance value of the first Acoustic Resistance block.

• R₂ is the resistance value of the second Acoustic Resistance block.

• r is the radius of the piston, derived from the Piston area parameter.

• ρ is the density of the fluid.

• c is the sound speed in the fluid.

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Ports

Conserving

+ — Positive terminal

acoustic

Acoustic conserving port associated with the positive terminal.

- — Negative terminal

acoustic

Acoustic conserving port associated with the negative terminal.

Parameters

Piston area — Area of circular piston

1 m² (default) | positive scalar

Area of the circular piston in m², specified as a positive scalar.

References

[1] Beranek, Leo Leroy, and Tim J. Mellow. Acoustics: Sound Fields, Transducers and Vibration. Second edition. Academic Press, 2019.

Version History

Introduced in R2026b