Small Concert Hall Acoustics
Designing structures and open spaces with respect to sound quality is important for concert halls, outdoor environments, and even the rooms of a house. Simulating acoustics in the high-frequency limit, where the wavelength is smaller than the geometrical features, can be done with ray acoustics. There are several advantages to modeling ray acoustics, including changing media properties and ...
Baffled Membrane
Learn how to use the Acoustic-Shell Interaction interface in this tutorial example of a thin vibrating membrane set in an infinite baffle. This example demonstrates how to model the acoustic interaction between a vibrating membrane and the surrounding air. In order to focus on the principles, the geometry is kept simple and the driving mechanism is not modeled.
Muffler with Perforates
Reflective mufflers are best suited for the low-frequency range where only plane waves can propagate in the system, while dissipative mufflers with fibers are efficient in the mid- to high-frequency range. Dissipative mufflers based on flow losses, on the other hand, also work at low frequencies. A typical automotive exhaust system is a hybrid construction consisting of a combination of ...
Sonic Well Logging
This model demonstrates how to simulate a piezoelectric transducer as both a sound transmitter and a receiver in a well logging setup. Other applications of this setup are, for example, in the field of nondestructive testing. A transmitting transducer is connected to an electrical circuit which is set up to send out a pulse as a detecting signal and also pick up the signals that come back to the ...
Flow Duct
The modeling of aircraft-engine noise is a central problem in the field of computational aeroacoustics. The acoustic field in a model of an axially symmetric aero-engine duct, generated by a noise source at the boundary, is computed and visualized. Results are presented for situations with as well as without a compressible irrotational background flow and for the cases of hard and lined duct ...
Noise Radiation by a Compound Gear Train
Predicting the noise radiation from a dynamic system gives designers insight into the behavior of moving mechanisms early in the design process. For example, consider a gearbox in which the change in the gear mesh stiffness causes vibrations. These vibrations are transmitted to the gearbox housing through shafts and joints. The vibrating housing further transmits energy to the surrounding fluid, ...
Nonlinear Slit Resonator: Coupling Acoustics and CFD
In many applications, acoustic waves interact with surfaces that have small perforations or slits. This can be in muffler systems; in soundproofing structures; in liners for noise suppression in jet engines; or in grilles and meshes in front of, for example, miniature speakers in mobile devices. At medium to high sound pressure levels, the local particle velocity in the narrow region of the ...
Gaussian Pulse in 2D Uniform Flow: Convected Wave Equation and Absorbing Layers
This tutorial simulates a standard test and benchmark model for nonreflecting conditions and sponge layers for linearized Euler-like systems. It involves the propagation of a transient Gaussian pulse in a 2D uniform flow. The *Convected Wave Equation, Time Explicit* interface solves the linearized Euler equations with an adiabatic equation of state and the interface uses the Absorbing Layers ...
Spherical Piezoacoustic Transducer
This tutorial provides a step-by-step instruction to setup a fully-coupled 3D structural-acoustic interaction problem. Interaction between a vibrating spherical piezoelectric structure with the surrounding fluid media is considered. The piezoelectric material PZT-5H from the materials library is used. Instructions on how to create a radially polarized piezoelectric material in spherical ...
Acoustic Muffler with Thermoviscous Acoustic Impedance Lumping
This model utilizes the thermoviscous acoustic interface in a sub-model to obtain detailed results for the transfer impedance of a perforated plate (including the thermal and viscous losses). The impedance is in turn used as an internal impedance in a pressure acoustic model of a muffler. The results are compared to classic impedance models and measurements.
