Tips & Tricks

Walter Frei | August 2, 2013

The COMSOL Optimization Module includes both gradient-based and gradient-free optimization techniques. Whereas the gradient-based optimization method can compute an exact analytic derivative of an objective function and any associated constraint functions, it does require these functions to be smooth and differentiable. In this blog post, we examine the use of the gradient-free optimizer, which can consider objective function and constraints that are not differentiable or smooth. The dimensions of a spinning wheel are optimized to reduce the mass while maintaining […]

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Bjorn Sjodin | May 28, 2013

Curvilinear coordinates are a coordinate system where the coordinate lines may be curved. The new user interface for automatic computation of curvilinear coordinates is a very practical addition to version 4.3b for those working with anisotropic materials in free-form CAD designs. If you have a generic bent shape and try to apply the usual coordinate systems like Cartesian, cylindrical, or spherical, you are out of luck. Curvilinear coordinates are needed to smoothly follow the design, which typically has no mathematical […]

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Chandan Kumar | April 3, 2013

Some structural applications involve thin or high aspect ratio structures sandwiched between other relatively low aspect ratio structures. For example, if a piezoelectric transducer is glued on the surface of a mechanical system, the thickness of the adhesive layer is very small in comparison to the two structures it glues together. Numerical modeling of such a thin layer in two or three dimensions requires resolving it with an appropriate finite element mesh. This can result in a large concentration of […]

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Bethany Moatts | March 22, 2013

Looking for ways to cut down on the time and computer memory required to run your simulation? Does your model exhibit some form of symmetry — axial symmetry, lines or planes of symmetry, or antisymmetry for example? Or perhaps your model exhibits periodicity? If you answered yes to those questions, you’re in luck. You can model symmetry or periodicity in COMSOL Multiphysics easily by either using a 1D or 2D axisymmetric dimensional simulation or by incorporating boundary conditions that represent […]

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Walter Frei | March 20, 2013

There is sometimes a need to include data from other simulation packages into a COMSOL Multiphysics model. There are a variety of ways in which this can be done, but one of the easiest approaches is to read in the point cloud data via a spreadsheet format text file. In this blog post, we walk through the steps of reading in such data, and using it in a COMSOL model.

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Bjorn Sjodin | March 19, 2013

For a transient simulation, imagine if you could simply insert a virtual sensor in a model at a certain location and then monitor the evolution of a field value over time while solving. In COMSOL Multiphysics you can do just that by using Probes. You define a probe in the Model Builder tree right under the Model Definitions node. Measuring the value at a point is not the only thing you can do with probes, but in this blog post […]

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Valerio Marra | January 14, 2013

We have written several blog posts on postprocessing already, but none detailing postprocessing for CFD. Postprocessing has always been an important part of my teachings, as you learn how to use COMSOL Multiphysics while also gaining insight into the physics at hand. I would like to share with you part of the classwork I proposed when teaching a CFD training course not long ago.

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Bethany Moatts | November 2, 2012

I’m back on the blog with the latest installment in the Postprocessing and Visualization Videos series. The two-part video shown here covers “Basic Visualization”. Chapter 1 and 2 will give you an overview of COMSOL’s visualization tools so that you can optimize how you view your model, both while setting up your physics and while postprocessing. I explain two tricks in the video that I’d like to draw your attention to in particular.

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Niklas Rom | October 11, 2012

Oftentimes when you are working with devices with internal fluid flow, the imported CAD design represents the vessel material. The inside is plainly void. This may leave you clueless since it is inside where you want to create a volume mesh for the flow equations. How can you solve this meshing problem in COMSOL?

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David Kan | September 25, 2012

I give a lot of COMSOL workshops — about 20 so far this year. These are great events and they include hands-on minicourses, which allow me to connect with the audience. One topic that I often spend a few minutes on might surprise you: icons. The icons, especially those found at the nodes in the Model Builder, are packed with useful information. They’re easy to miss because they’re small, but knowing what they mean can be a big help.

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Bethany Moatts | August 28, 2012

Would you like to plot your own expressions in COMSOL? Have you ever wanted the power to measure parameters from your virtual model at whatever point you’d like, just as you would in a physical model? This new postprocessing tutorial video duo explains how to create 1D plots in COMSOL.

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