Model Gallery
Point Source in 2D Jet: Radiation and refraction of sound waves through a 2D shear layer - new
This is a benchmark model for the linearized Euler interface of the Acoustics Module. The model is from the NASA "Fourth Computational Aeroacoustics (CAA) Workshop on Benchmark Problems (2004)". The model results are compared to an analytical solution by Agarwal et al. (AIAA Vol. 42, No. 1, January 2004). A point source is located in a narrow 2D jet of Mach 0.8. The model investigates the ...
Jet Pipe
This example models the radiation of fan noise from the annular duct of a turbofan aeroengine. When the jet stream exits the duct, a vortex sheet appears along the extension of the duct wall due to the surrounding air moving at a lower speed. The near field on both sides of the vortex sheet is calculated. The Aeroacoustics modeling interface in the Acoustics Module describes acoustic waves in a ...
Sedan Interior Acoustics - new
This is a model of the acoustics inside a sedan, that is inside a typical hard-top family car. The model sets up sources at loudspeaker locations as well as impedance conditions to model soft absorbing surfaces (seats and carpet). The model results in plots of the pressure, sound pressure level, and intensity inside the car. The frequency response at given points inside the cabin are also ...
Lumped Receiver Connected to Test Set-up with an 0.4-cc Coupler
In this model a Knowles ED23146 receiver (miniature loudspeaker) is connected to a test set-up consisting of a 50 mm (1 mm diameter) earmold tube and a so-called 0.4-cc coupler. The receiver is modeled using a lumped spice network and connected to the finite element domain at the tube inlet. The response at the measurement microphone in the coupler as well as the electric input impedance to the ...
One-Family House Acoustics
This model shows an application of the Acoustic Diffusion Equation physics interface. The acoustics in a two story one-family house consisting of 10 rooms is analyzed. The steady state sound pressure level (acoustic energy density) distribution is analyzed for a sound source located in the main living room. The reverberation time T60 of the different coupled rooms is then studied using the ...
Eigenmodes in a Muffler
In this model, compute the propagating modes in the chamber of an automotive muffler. The geometry is a cross-section of the chamber in the Absorptive Muffler example. The model’s purpose is to study the shape of the propagating modes and to find their cut-off frequencies. As discussed in the documentation for the Absorptive Muffler, some of the modes significantly affect the damping of the ...
Acoustic Muffler with Thermoacoustic Impedance Lumping
This model utilizes the thermoacoustic interface in a submodel to obtain a detailed (and more precise) measure for the transfer impedance of a perforated plate. The impedance is in turn used as an internal impedance in a pressure acoustic model of a muffler. Results are compared to classic impedance models.
Uniform Layer Waveguide
Whenever dimensions in waveguides become small compared to the viscous and thermal boundary layers it is necessary to model acoustics using thermoacoustics. In the present model the thermoacoustic wave field in a shallow uniform waveguide is modeled and compared to an analytical solution.
Doppler Shift
We have all noticed the Doppler effect when an ambulance passes by with its sirens blaring. The siren’s pitch suddenly drops the moment the ambulance starts moving away from you. Another effect you can notice is how the siren’s sound is very loud when nearby, but as soon as the ambulance has passed the sound becomes much quieter. This model simulates the acoustic Doppler effect by ...
Bessel Panel
The Bessel panel is a way to arrange a number of loudspeakers so that the angular sound distribution resembles that of a single speaker. This model combines five Bessel panels in the same pattern to approximate a purely radial sound field. The speakers are driven with different signals, some of them in counter-phase. This results in an approximately homogeneous polar far-field ...
