Example12 Acoustic Impedance

Acoustic impedance is set on Exercise 2’s model to see the effect of air resistance.

Item	Settings
Solvers	Piezoelectric Analysis [Rayleigh]
Analysis Type	Harmonic analysis
Options	N/A

The harmonic analysis tab is set up as follows.

Tab

Setting Item

Settings

Harmonic analysis

Frequency

Minimum: 5.6×10^3[Hz]

Maximum: 5.7×10^3[Hz]

Step

Select “Linear step by division number”.

Division number: 50

Boundary Condition Name/Topology	Tab	Boundary Condition Type	Settings
Outer Boundary Condition	Mechanical	Acoustic Impedance	409.7[Pa*s/m]
earth/Face	Electric	Electric wall	Voltage specified: Voltage 0[V]
hot/Face	Electric	Electric wall	Voltage specified: Voltage 1[V]
hot/Face	Mechanical	Acoustic Impedance	409.7[Pa*s/m]

The outer boundary condition and “hot” ad set with the “acoustic impedance” boundary condition.

409.7[Ns/m3] is the acoustic impedance of air.

For comparison, the simulation is done for the acoustic impedance of 0[Ns/m3] and 100[Ns/m3] as well as 409.7[Ns/m3].

The frequency characteristics of electric impedance are plotted below.

The right figure is a blow up of the left.

Note that the legends of the series titles are not created by the graphing software.