## Understanding the Different Elements of Gear Modeling

##### Pawan Soami October 18, 2016

To accurately simulate a gear and obtain useful results, it is important to consider a number of elements behind the device’s design and how they are modeled. New features and functionality in the COMSOL Multiphysics® software provide you with the tools to address such properties and thus advance the reliability of your simulation studies. Today, we’ll review the various elements of gear modeling and explain how to account for them in our modeling processes.

Read More##### Bridget Paulus October 17, 2016

Developing a device that generates nuclear fusion would provide a nearly limitless amount of clean energy on Earth. But while work on thermonuclear fusion began in the 1950s, engineers are still trying to make this goal a reality. One approach has been to use magnetic confinement devices known as tokamaks. See why a group of engineers at MIT’s Plasma Science Fusion Center (PSFC) turned to simulation to address a key challenge in tokamak design: instability due to plasma disruptions.

Read More##### Lauren Sansone October 13, 2016

Experts in industry and academia joined us from near and far at the COMSOL Conference 2016 Boston last week. It was a great event for connecting, learning, and innovating — and now that it’s over, we’d like to share some photos and attendee feedback with you.

Read More##### Caty Fairclough October 12, 2016

Last week, users of COMSOL Multiphysics® presented innovative projects at the COMSOL Conference 2016 Boston. Topics ranged from the human body to acoustic black holes, and while it was hard to pick favorites, a few of the submissions stood out above the rest. Attendees voted for their favorite poster and our committee selected six of the best papers and posters. Curious about who won? Here’s a round-up of the top papers and posters from the COMSOL Conference 2016 Boston…

Read More##### Ed Gonzalez October 11, 2016

Many polymers and biological tissues exhibit viscoelastic deformation, which has a time-dependent response even if the loading is constant in time. Linear viscoelasticity, where the stress depends linearly on the strain and strain rate, is a common approximation. We usually assume that the viscous part of the deformation is incompressible, so the volumetric deformation is purely elastic. In COMSOL Multiphysics® 5.2a, you can model large-strain viscoelasticity besides linear viscoelasticity. See how to use this material model in a biomedical application.

Read More##### Caty Fairclough October 10, 2016

Mixers are used for different purposes in many modern industries. If you are looking for an efficient mixer design process, you need a simulation tool that enables you to mix and match different mixer elements. With the COMSOL Multiphysics® software, you can create a mixer geometry that fits your own needs. Today, we’ll discuss modeling a laminar mixing problem with a flat-bottom mixer and two turbulent mixing problems with dished-bottom mixers that utilize the k-epsilon and k-omega turbulence models.

Read More##### Amlan Barua October 7, 2016

In 1961, R. Fitzhugh (Ref. 1) and J. Nagumo proposed a model for emulating the current signal observed in a living organism’s excitable cells. This became known as the FitzHugh-Nagumo (FN) model of mathematical neuroscience and is a simpler version of the Hodgkin-Huxley (HH) model (Ref. 2), which demonstrates the spiking currents in neurons. In today’s blog post, we’ll examine the dynamics of the FN model by building an interactive app in the COMSOL Multiphysics® software.

Read More##### Temesgen Kindo October 6, 2016

In a previous blog post, we discussed integration methods in time and space, touching on how to compute antiderivatives using integration coupling operators. Today, we’ll expand on that idea and show you how to analyze spatial integrals over variable limits, whether they are prescribed explicitly or defined implicitly. The technique that we will describe can be helpful for analyzing results as well as for solving integral and integro-differential equations in the COMSOL Multiphysics® software.

Read More##### Temesgen Kindo October 5, 2016

Cylindrical coordinates are useful for efficiently solving and postprocessing rotationally symmetric problems. The COMSOL Multiphysics® software has built-in support for cylindrical coordinates in the axisymmetry physics interfaces. When defining custom partial differential equations (PDEs) using the mathematical interfaces, paying close attention to their meaning is important. The PDE interfaces assume partial differentiation in a Cartesian system, requiring manual coordinate transformations to change to a cylindrical system. See how to account for such coordinate transformations when using your own PDEs.

Read More##### Bridget Cunningham October 4, 2016

Environmental demands for greater fuel efficiency and lower emissions have sparked an interest in finding an alternative to traditional spark- and compression-ignition engines. While homogeneous charge compression ignition (HCCI) engines offer a viable solution, significant challenges like maintaining control of ignition timing still remain. With simulation tools like the COMSOL Multiphysics® software, you can analyze the combustion process of an HCCI engine and gain deeper insight into ways to advance ignition control.

Read More##### Linus Andersson September 29, 2016

Perforations, in mufflers for example, enable partial sound transmission between chambers as well as in and out of pipes. When simulating perforates, it’s possible to draw and mesh each hole, but this increases the time it takes to solve the model. For a more efficient approach, we can apply a semitransparent boundary. Here, we’ll discuss several techniques for doing so as well as describe a method for computing the transfer impedance of the perforate.

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