The Application Gallery features COMSOL Multiphysics® tutorial and demo app files pertinent to the electrical, structural, acoustics, fluid, heat, and chemical disciplines. You can use these examples as a starting point for your own simulation work by downloading the tutorial model or demo app file and its accompanying instructions.

Search for tutorials and apps relevant to your area of expertise via the Quick Search feature. To download the MPH-files, log in or create a COMSOL Access account that is associated with a valid COMSOL license. Note that many of the examples featured here can also be accessed via the Application Libraries that are built into the COMSOL Multiphysics® software and available from the File menu.

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COMSOL News Magazine 2017

Stress Relaxation of a Viscoelastic Tube

This model studies the temperature effects on the viscoelastic stress relaxation in a long thick-walled cylinder. In particular, decay of the stresses under the influence of the temperature field during a period of two hours is studied. A four-term generalized Maxwell model represents the material.

Radome with Double-layered Dielectric Lens

A radome minimizes losses and improves radiation characteristics of an antenna through its design. The structure can be optimized to minimize the transmission loss and also designed to improve radiation characteristics including antenna directivity and side lobes. Shown in the model is the surface current density on the patch antenna, the magnitude of the electric potential on the antenna's ...

Simply Supported Beam Rotor

In this tutorial model, you will see how to set up eigenfrequency and transient analyses (using FFT) of a rotor with various mountings and bearing supports. The example illustrates how to use Campbell and Waterfall plots to find the critical speed. It also demonstrates the range of stability of the rotor. The rotor is modeled using the *Beam Rotor* interface in the Rotordynamics Module, an add ...

Vibrating Micromirror with Viscous and Thermal Damping: Transient Behavior

Micromirrors are used in certain MEMS devices to control optic elements. This example model illustrates a mirror that is initially actuated for a short time and then exhibits damped vibrations. It simulates a vibrating micromirror surrounded by air and uses the *Thermoviscous Acoustics, Transient*, the *Shell*, and the *Pressure Acoustics, Transient* interfaces to model the fluid-solid ...

Bessel Panel

The Bessel panel is a way to arrange a number of loudspeakers so that the angular sound distribution resembles that of a single speaker. This model combines five Bessel panels in the same pattern to approximate a purely radial sound field. The speakers are driven with different signals, some of them in counter-phase. This results in an approximately homogeneous polar far-field distribution. ...

Tilted Pad Thrust Bearing

Tilted pad thrust bearings are used in rotating machineries with high thrust loading. The thrust load is transferred from a sliding part to a stationary part through hydrodynamic oil films. The tilted pad thrust bearing consists of a series of flat surfaces sliding over stationary tilted pads. The space between the flat surface and the tilted pad is filled by a lubricant that is drawn in due to ...

Spring Loaded Centrifugal Governor

A centrifugal governor is used to control the speed of rotating machinery. One of the most common applications is in controlling the RPM of an engine by regulating the fuel supply. This model illustrates the functioning of a spring loaded centrifugal governor. The dynamics of the governor are analyzed under the influence of a centrifugal force, spring force, and damping force. The sleeve ...

Tunable Evanescent Mode Cavity Filter Using a Piezo Actuator

An evanescent mode cavity filter can be realized by adding a structure inside of the cavity. This structure changes the resonant frequency lower than the dominant mode of the unfilled cavity. A piezo actuator is used to control the size of a small air gap which provides the tunability of the resonant frequency.

Truss Bridge Designer

The Truss Bridge Designer app is an example of how to design a simulation tool for a class of civil engineering structures, in this case a Pratt truss bridge. Such a bridge is characterized by the diagonal beams on each side of the bridge, which all slant down and in toward the center of the span. Because of this design, the diagonal beams are subjected only to tension, while the vertical beams, ...

Sub-Component Lumping in Acoustics Using the Impedance Boundary Condition

This application illustrates a modeling approach for deriving physically consistent simplified models in the Acoustics Module. The approach consists of converting complex sub-components to an impedance boundary condition and otherwise using simple acoustics throughout the COMSOL model. As a consequence, significant computational speed-up can be achieved. The example treated here consists of a ...