# Application Gallery

The Application Gallery features COMSOL Multiphysics tutorial and demo app files pertinent to the electrical, mechanical, fluid, and chemical disciplines. You can download ready-to-use tutorial models and demo apps with step-by-step instructions for how to create them yourself. The examples in the gallery serve as a great starting point for your own simulation work.

Use the Quick Search to find tutorials and apps relevant to your area of expertise. Log in or create a COMSOL Access account that is associated with a valid COMSOL license to download the MPH-files.

### 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 ...

### 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 ...

### Test Bench Car Interior

Sound is generated by a point source located in the wall of this test bench car interior. The sound pressure level response at a point of measurement is investigated for a range of frequencies and four different mesh resolutions. The model is first solved with the default direct solvers. Finally, it is shown how to set up an iterative solver which is efficient for large problems and the finest ...

### Apartment Acoustics Analyzed using the Acoustic Diffusion Equation

The sound distribution from a TV in a two-room apartment is computed. The simulation demonstrates the use of the Acoustic Diffusion Equation interface to get a quick and simple estimate of the local sound pressure level. For increased accuracy, an analytical expression for the direct sound is added in the living room.

### Axisymmetric Condenser Microphone with Electrical 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.

### 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 ...

### 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 ...

### Probe Tube Microphone

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 ...

### 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.