AcousticImpedanceValue
AcousticImpedanceValue[pred,vars,pars]
represents a time or frequency domain impedance boundary condition for PDEs with predicate pred indicating where it applies, with model variables vars and global parameters pars.
AcousticImpedanceValue[pred,vars,pars,lkey]
represents a time or frequency domain boundary condition with local parameters specified in pars[lkey].
Details
- AcousticImpedanceValue specifies a boundary condition for AcousticPDEComponent and is used as part of the modeling equation:
- AcousticImpedanceValue is typically used to model a boundary material that is partially transparent to sound.
- AcousticImpedanceValue models a time or frequency domain impedance with dependent variable pressure
in 
, independent variables 
in 
and time variable 
in 
or frequency variable 
in 
. - Time-dependent variables vars are vars={p[t,x1,…,xn],t,{x1,…,xn}}.
- Frequency-dependent variables vars are vars={p[x1,…,xn],ω,{x1,…,xn}}.
- The time domain acoustics model AcousticPDEComponent is based on a wave equation with time variable
, density 
, sound speed 
and sound sources 
and 
: - The frequency domain acoustics model AcousticPDEComponent is based on a Helmholtz equation with angular frequency
: - The time domain impedance value AcousticImpedanceValue with impedance
in 
and boundary unit normal 
models: - The frequency domain impedance value AcousticImpedanceValue models:
- Model parameters pars are specified as for AcousticPDEComponent.
- The following model parameters pars can be given:
-
parameter default symbol "SpecificAcousticImpedance" Infinity 
, acoustic impedance in 
- AcousticImpedanceValue evaluates to a generalized NeumannValue.
- The boundary predicate pred can be specified as in NeumannValue.
- An impedance boundary can be used with:
-
analysis type applicable Time Domain Yes Frequency Domain Yes Eigenfrequency No - If the AcousticImpedanceValue depends on parameters
that are specified in the association pars as …,keypi…,pivi,…], the parameters 
are replaced with 
.
Examples
open allclose allBasic Examples (5)
Set up a time domain acoustic impedance boundary:
Set up a frequency domain acoustic impedance boundary:
Set up a time-independent acoustic impedance boundary:
Define model variables vars for a transient acoustic pressure field with model parameters pars:
Define initial conditions ics of a right-going plane wave 
:
Set up the equation with an acoustic impedance boundary at the right and an impedance 
of 
:
Define model variables vars for a frequency domain acoustic pressure field with model parameters pars:
Set up the equation with a radiation boundary at the left, an acoustic impedance boundary at the right and an impedance 
of 
:
Visualize the solution in the frequency domain at various frequencies 
:
Scope (2)
Possible Issues (1)
The default value for "SpecificAcousticImpedance" is Infinity:
Text
Wolfram Research (2020), AcousticImpedanceValue, Wolfram Language function, https://reference.wolfram.com/language/ref/AcousticImpedanceValue.html.
CMS
Wolfram Language. 2020. "AcousticImpedanceValue." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/AcousticImpedanceValue.html.
APA
Wolfram Language. (2020). AcousticImpedanceValue. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/AcousticImpedanceValue.html