# モデル・ギャラリー

The Model Gallery features COMSOL Multiphysics model files from a wide variety of application areas including the electrical, mechanical, fluid, and chemical disciplines. You can download ready-to-use models and step-by-step instructions for building the model, and use these as a starting point for your own modeling work. Use the Quick Search to find models relevant to your area of expertise, and login or create a COMSOL Access account that is associated with a valid COMSOL license to download the model files.

### 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 ...

### Jet Pipe

This example models the radiation of fan noise from the annular duct of a turbofan aeroengine. When the jet stream exits the duct, a vortex sheet appears along the extension of the duct wall due to the surrounding air moving at a lower speed. The near field on both sides of the vortex sheet is calculated. The Aeroacoustics modeling interface in the Acoustics Module describes acoustic waves in a ...

### Absorptive Muffler with Shells

This model describes the pressure wave propagation in a muffler for an internal combustion engine. The purpose of the model is to show how to analyze both inductive and resistive damping in pressure acoustics as well as coupling the fluid to the surrounding elastic shell structure of the muffler. Finally, the eigenmodes of a pure structural problem is analyzed and the modes compared to peaks in ...

### Eigenmodes in a Muffler

In this model, compute the propagating modes in the chamber of an automotive muffler. The geometry is a cross-section of the chamber in the Absorptive Muffler example. The model’s purpose is to study the shape of the propagating modes and to find their cut-off frequencies. As discussed in the documentation for the Absorptive Muffler, some of the modes significantly affect the damping of the ...

### Two-port Piezoelectric SAW Device

This tutorial shows how to model surface acoustic waves in time domain. The 3D modeling geometry represents a 128 degree YX-cut lithium niobate substrate. The SAW device has two ports. The metallic electrodes are modeled as perfect conductors using boundary conditions. The geometric dimensions such as size of substrate, the gap between the ports and the number of inter-digitated electrodes (IDTs) ...

### Acoustic Muffler with Thermoacoustic Impedance Lumping

This model utilizes the thermoacoustic interface in a submodel to obtain a detailed (and more precise) measure for the transfer impedance of a perforated plate. The impedance is in turn used as an internal impedance in a pressure acoustic model of a muffler. Results are compared to classic impedance models.

### Lumped Receiver Connected to Test Set-up with an 0.4-cc Coupler

In this model a Knowles ED23146 receiver (miniature loudspeaker) is connected to a test set-up consisting of a 50 mm (1 mm diameter) earmold tube and a so-called 0.4-cc coupler. The receiver is modeled using a lumped spice network and connected to the finite element domain at the tube inlet. The response at the measurement microphone in the coupler as well as the electric input impedance to 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, ...

### One-Family House Acoustics

This model shows an application of the Acoustic Diffusion Equation physics interface. The acoustics in a two story one-family house consisting of 10 rooms is analyzed. The steady state sound pressure level (acoustic energy density) distribution is analyzed for a sound source located in the main living room. The reverberation time T60 of the different coupled rooms is then studied using the ...

### Microphone grid free-field level correction curve for plane-wave incidence

This is a conceptual model of a microphone placed in an infinite baffle (flush mounted). The purpose is to determine the free-field level correction curve of the setup, which includes the exterior domain, microphone grid, and volume between the grid and the diaphragm. The microphone diaphragm is characterized with a simple RCL impedance and the open radiation condition is modeled with a Perfectly ...