Model Gallery
Acoustic Cloaking
Two articles in the New Journal of Physics describe how to derive necessary conditions on an anisotropic density tensor to create a perfect acoustic cloak in 2D, and show how this material can be realized in practice as a layered shell with isotropic properties in each layer. These two example files illustrate simplest possible implementations using both anisotropic density and the layered ...
Vibrating Micromirror with Viscous and Thermal Damping
Micromirrors are used in certain MEMS devices to control optic elements. This model of a vibrating micromirror surrounded by air uses the Thermoacoustic-Shell Interaction user interface to model the fluid-solid interaction, and it thus includes the correct viscous and thermal damping of the mirror from the surrounding air. The resonance frequency of the mirror when under a torquing load is ...
Acoustic Reflections off a Water-Sediment Interface - new
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 ...
Axisymmetric Condenser Microphone
This is a model of a condenser microphone with a simple axisymmetric geometry. The model aims to give a precise description of the physical working principles of such a microphone. The condenser microphone is considered to be the microphone with highest quality when performing precise acoustical measurements and with high-fidelity reproduction properties when performing sound recordings. This ...
Condenser Microphone, Axisymmetric with Electric Lumping
This model is that of a simple axisymmetric condenser microphone. The model includes all the relevant physics and determines the sensitivity of the specific microphone geometry and material parameters. The model uses a lumped approximation for the electric small signal problem but solves a full FE model for the acoustic-mechanical system. The quiescent (zero point) problem is solved fully using ...
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.
Photoacoustic Resonator
This is a model of a simple photoacoustic (or optoacoustic) resonator. A pulsating laser heats a gas causing expansion and contraction and thus creates pressure waves. Such devices are used as sensors for measuring material parameters of the gas inside the resonator. The resonance frequency of the system depends on the gas in the resonator. The model uses the thermoacoustic interface with a ...
Acoustics of a Particulate-Filter-Like System
This is the model of the acoustics in a particulate-filter-like system. Real systems, like diesel particulate filters (DPFs), are designed to remove/filter soot (diesel particles) from the exhaust of diesel engine vehicles. The porous medium in such systems are typically structured with long air filled slits/chanels. In this 2D axisymmetric model the filter is approximated with a porous material ...
Cylindrical Subwoofer
In this model, the acoustic field inside and outside a down-firing subwoofer is computed. This model is set up in 2D axisymmetry using the Pressure Acoustics application mode. The modeled physical domain is a hemisphere with a radius of 1 m. To minimize the effect of non-physical reflections at the exterior boundary of this domain, an absorbing Perfectly Matched Layer (PML) is added. The ...
Vibrating Particle in Water: Correct Thermoacoustic Material Parameters
This is a tutorial model that simulates a small vibrating hemispherical particle in water. The vibrations induce acoustic waves in the fluid. The model shows how to set up the material parameters in a thermoacoustic model to get the correct acoustic (compressible) waves in the fluid.
