Galleria dei Modelli

La Galleria dei Modelli raccoglie un'ampia varietà di modelli realizzati con COMSOL Multiphysics in diversi ambiti applicativi, inclusi quelli elettrico, meccanico, fluidico e chimico. E' possibile scaricare i file .mph dei modelli pronti all'uso e le istruzioni step-by-step per costruirli, e utilizzarli come punto di partenza per le proprie simulazioni. Lo strumento di Ricerca Rapida permette di trovare i modelli che si riferiscono alla propria area di interesse. Per scaricare i file .mph dei modelli è necessario effettuare il login o creare un account COMSOL Access associato a un numero di licenza valido.

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 ...

Vibrations of a Disk Backed by an Air-Filled Cylinder

The vibration modes of a thin or thick circular disc are well known, and it is possible to compute the corresponding eigenfrequencies to arbitrary precision from a series solution. The same is true for the acoustic modes of an air-filled cylinder with perfectly rigid walls. A more interesting question to ask is: What happens if the cylinder is sealed in one end not by a rigid wall but by a thin ...

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 ...

Radially Polarized Piezoelectric Transducer

This tutorial model shows how a user-defined coordinate system can be used to create any type of directional polarization of a piezoelectric material. Results are shown for the case of radial polarization of a piezoelectric disk. The piezoelectric material is PZT-5H. The example shows a static analysis. Visualization of the cylindrical coordinate system as well as the stress/strain in that system ...

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 ...

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.

Point Source in 2D Jet: Radiation and refraction of sound waves through a 2D shear layer

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 ...

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 ...

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 ...

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