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.

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 ...

Open Pipe

In this model, sound created by a vibrating piston radiates through a baffled pipe. The impedance is measured and then used in an impedance boundary condition that replaces the surrounding air domain. This technique can be employed to reduce solution time and memory usage for large models with pipe openings.

Lumped Loudspeaker Driver

This is a model of a moving-coil loudspeaker where a lumped parameter analogy represents the behavior of the electrical and mechanical speaker components. The Thiele-Small parameters (small-signal parameters) serve as input to the lumped model, which is represented by an Electric Circuit physics. The lumped model is coupled to a 2D axisymmetric Pressure Acoustics model describing the surrounding ...

Transient Gaussian Explosion

An ellipse with sound-hard walls has the interesting property that an acoustic signal emanating from one of the foci refocuses at the other focal point b/c seconds later, where b (in meters) is the major axis length and c (m/s) is the speed of sound. This model involves a Gaussian explosion at one focus of an ellipse to illustrate some properties of time-dependent acoustic problems. The ...

Generic 711 Coupler: An Occluded Ear-Canal Simulator

This is the model of an occluded ear canal simulator (a generic 711 coupler). Besides certain details the geometry corresponds to the Brüel & Kjær Ear Simulator Type 4157. The real life couplers are used for simulating the acoustics of a standardized human ear canal and can be used for measurements on all sorts of devices. They are widely used in the hearing aid industry but also as ear ...

Probe Tube Microphone, Transient Model

It is often not possible to insert a normal microphone directly into the sound field being measured. The microphone may be too big to fit inside the measured system, such as for in-the-ear measurements for hearing aid fitting. The size of the microphone may also be too large compared to the wavelength, so that it disturbs the acoustic field. In these cases, a probe tube may be attached to the ...

Acoustic Levitator

An ultrasonic standing wave levitator, also called acoustic levitator, is a device used for levitating fluid and solid particles in an acoustic field. The standing acoustic waves exert an acoustic radiation force on the particles. The force is a second order effect and stems from a combination of the time averaged pressure and inertial interaction between the particles and the acoustic field. By ...

Acoustic Scattering Off an Ellipsoid

This is a tutorial model that illustrates the use of the scattered field formulation in acoustics. A solid object (here an ellipsoid) is hit by an incident plane wave field (background pressure field). The model solves for the scattered field. The model uses a PML and a far-field calculation is also added. The mesh is set up to enhance the PML and the far-field performance. ...

Porous Absorber

This is a model of acoustic absorption by a porous acoustic open cell foam. In porous materials the sound propagates in a network of small interconnected pores. Because the dimensions of the pores are small, losses occur due to thermal conduction and viscous friction. Acoustic foams are used to sound proof rooms and ducts as well as to treat reverberation problems in rooms. The aim of the ...

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 ...

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