What Is the Doppler Effect?

Brianne Costa May 29, 2018

The Doppler effect, or Doppler shift, occurs when the movement of an observer relative to a source (or vice versa) causes a change in wavelength or frequency. Discovered by Austrian physicist Christian Doppler in 1803, this phenomenon is experienced in many different ways, such as when an ambulance passes you by and you hear an audible change in pitch. Using the COMSOL Multiphysics® software, you can model the Doppler effect for acoustics applications.

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Brianne Costa May 11, 2018

Shape memory alloys (SMAs) are alloys with “memory”: They can return to their original shape after being deformed via a change in pressure or temperature. SMAs are used in a wide variety of applications — including metallurgy, manufacturing, biomedicine, and children’s arts and crafts — and their uses are always expanding…

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Caty Fairclough April 27, 2018

Picture a classroom filled with students. At the front, a teacher discusses room acoustics, including the underlying theories and acoustics phenomena involved. To help students visualize these concepts, the teacher has created a simulation app. This app, which is accessible through a web browser, enables students to dynamically alter parameters and see the results, creating a vivid learning experience. At the Technical University of Munich (TUM), several such apps are already being used, providing benefits to teachers and students alike…

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Ravi Ranjan April 18, 2018

When working with multibody systems, you may need to model a mechanism that transfers motion from one component to another. The mechanism used to implement this behavior, known as a cam-follower mechanism, plays an important role in many applications, including internal combustion engines, printing control mechanisms, textile weaving machines, and valves. You can easily model this type of mechanism with the Cam-Follower feature in the COMSOL® software. Let’s take a look at this feature in detail.

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Walter Frei April 17, 2018

In applications such as power transfer and consumer electronics, it may be critical to model electromagnetic heating of materials that are nonlinear in temperature; that is, the material’s electrical conductivity and thermal conductivity vary with temperature. When modeling these nonlinearities, even an experienced analyst can sometimes get quite unexpected results due to the combination of the nonlinear material properties, boundary conditions, and geometry. Let’s find out why this is in terms of a very simple example.

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Henrik Sönnerlind April 13, 2018

When a tuning fork is struck, and held against a tabletop, the peak frequency of the emitted sound doubles — a mysterious behavior that has left many people baffled. In this blog post, we explain the tuning fork mystery using simulation and provide some fun facts about tuning forks along the way.

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Mads Herring Jensen March 19, 2018

The boundary element method (BEM) is included in the Acoustics Module as a physics interface. This interface, available as of version 5.3a of the COMSOL Multiphysics® software, can be seamlessly combined with interfaces based on the finite element method (FEM) to model, for example, acoustic-structure interaction problems. This functionality expands the range of problems that can be solved with the Acoustics Module. Here, we look into the BEM functionality, examples, and BEM-specific postprocessing.

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Nicolas Huc March 15, 2018

Nonisothermal flow combines CFD and heat transfer analysis. In cases where the temperature of the fluid at an inlet is a known quantity, a Temperature boundary condition can be used. However, there are some important situations where this is not the case, and an Inflow boundary condition can improve the model accuracy and reduce the computational cost of the simulation. Here, we review how this more sophisticated thermal boundary condition can be set at a flow inlet.

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Guest Mandar Gadgil March 12, 2018

Guest blogger Mandar Gadgil of Noumenon Multiphysics discusses modeling phase change in a thermosiphon. Thermosiphons have been used for keeping houses warm since the 1800s. These devices use central heaters and pipe networks that carry water and steam to different rooms. The cool part (figuratively) is that no pump is needed for fluid transport — convective currents induced by the heater located at the bottom of an installation are enough. Let’s discuss modeling thermosiphons using a “pseudofluid” with temperature-dependent properties.

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Caty Fairclough March 7, 2018

Additive manufacturing has a wide array of applications, such as creating custom medical devices, aerospace components, and artwork. With the list of potential uses continuing to grow, it’s important that this type of manufacturing can keep up with the demand. However, analyzing and optimizing this complex process can be difficult. What can engineers do to overcome this challenge?

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Thomas Forrister March 5, 2018

The foundation of a tunnel, dam, building, or other structure can be analyzed with a method called triaxial testing. Performing triaxial tests before, during, and after construction helps to ensure that structures are safe and reliable. To better understand the mechanics of soil and improve a structure’s stability, you can model the loading and unloading curves for a triaxial testing apparatus and test the soil’s model parameters in the COMSOL Multiphysics® software.

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