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Shape Optimization of a Tweeter Waveguide
This application illustrates how to use COMSOL’s optimization capabilities to automatically develop novel designs satisfying critical design constraints. The model optimizes a simple speaker geometry. Examples of constraints could include the radius of the loudspeaker or a desired minimum achievable sound-pressure level. To exemplify the optimization capabilities this application studies the ...
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 ...
Piezoelectric Tonpilz Transducer with a Prestressed Bolt
A tonpilz transducer is used for relatively low frequency, high power sound emission. It is one of the popular transducer configurations for SONAR applications. The transducer consists of piezoceramic rings stacked between a head mass and a tail mass which are connected by a central bolt. This example shows how to incorporate the effect of a pre-tension in the bolt. The bolt geometry is ...
Anechoic Coating
Anechoic coatings are used for lowering visibility to sonars, for example on submarines. This model calculates the reflection, absorption, and transmission properties of an anechoic coating on a steel plate based on a setup from literature.
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.
Optimizing the Shape of a Horn
A plane-wave mode feeds an axisymmetric horn radiating from an infinite baffle towards an open half space. The radius of the feeding waveguide is assumed to be fixed, as well as the depth of the horn and the size of the hole where the horn is attached to the baffle. By varying the curvature of the initially conical surface of the horn, its directivity and impedance can be changed. This model ...
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-Structure Interaction and Air Flow in Violins
These models are featured in the blog post [Analyze Violin Tone and Volume with Multiphysics Modeling](http://www.comsol.com/blogs/analyze-violin-tone-and-volume-with-multiphysics-modeling/). One applies acoustic-structure interaction to study how the air mode resonance is affected by the coupled vibrations in the violin body. The other uses a potential flow approximation to find out how the air ...
Acoustic Reflections off a Water-Sediment Interface
This model determines the reflection coefficient of plane acoustic waves, at different frequencies and at different angles of incidence, off a water-sediment interface. The ability of the Poroelasitc Waves interface to model the coupled acoustic and elastic wave in any porous substance (Biot's theory) is used to describe the water-sediment system. The model results are in good agreement with ...
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, ...
