## How to Automate Physics Choices and Studies Using Model Methods

##### Temesgen Kindo June 28, 2017

You solved a model under certain assumptions. When you analyze the results, you find out that those assumptions do not hold. Now, you have to amend your analysis by incorporating new physics features or changing the study type. What if you could automate such processes? Today, we will discuss how to do so easily using the Model Method feature introduced in version 5.3 of the COMSOL Multiphysics® software.

Read More##### Temesgen Kindo May 9, 2017

When your simulations consume significant memory, do you buy a bigger computer? When they take too long to solve, do you just run them overnight? Often, you don’t have another option. But sometimes, if you have the right tools, you can find a better approach by exploiting the mathematical structure. Today, we will show you how to use the so-called maximum principles to save computational resources and time in the COMSOL Multiphysics® software.

Read More##### Jeff Hiller December 20, 2016

Do you find yourself creating new models in the COMSOL Multiphysics® software faster than you can launch them interactively in the COMSOL Desktop® environment? If having to wait for your current model to finish solving before launching the next one does not sound appealing, it’s time to learn how to run your simulations in Batch mode from the command line. As it turns out, this is quite a simple process.

Read More##### Jan-Philipp Weiss November 25, 2016

In a recent blog post, we discussed how to use the Domain Decomposition solver for computing large problems in the COMSOL Multiphysics® software and parallelizing computations on clusters. We show how to save memory by a spatial decomposition of the degrees of freedom on clusters and single-node computers with the Recompute and clear option. To further illustrate the Domain Decomposition solver and highlight reduced memory usage, let’s look at a thermoviscous acoustics problem: simulating the transfer impedance of a perforate.

Read More##### Jan-Philipp Weiss November 23, 2016

The Domain Decomposition solver is a memory-efficient iterative algorithm with inherent parallelism on the geometric level. We can use this method to compute large modeling problems that can’t be solved with other direct or iterative methods. This solver’s primary field of application is on clusters, but it can also enable the solution of large problems on laptops and workstations. Let’s see how to use this functionality in the COMSOL Multiphysics® software.

Read More##### Magnus Ringh September 2, 2016

A COMSOL Multiphysics® simulation typically includes one or more field quantities in its output. Depending on the number of field quantities, the geometry’s complexity, and the mesh density required for valid results, simulations can include millions of degrees of freedom (DOFs). Oftentimes, storing one or more scalar quantities or the results on a small geometry part is sufficient. Here, we explore tools for storing selected output quantities and minimizing model file sizes and the time required to display this data.

Read More##### Magnus Ringh April 27, 2016

You can use the residual operator, new with COMSOL Multiphysics version 5.2, to evaluate and plot your model’s algebraic residual in order to troubleshoot convergence issues. This blog post demonstrates the use of the residual operator for visualizing and understanding the convergence properties of a turbulent flow simulation.

Read More##### Bjorn Sjodin February 2, 2016

Have you ever run a large parametric sweep overnight, only to discover the next morning that the parametric solver is still not finished? You may wish you could inspect the solutions for the parameters that are already computed while waiting for the last few parameters to converge. The remedy to this problem is to use a batch sweep, which automatically saves the parametric solutions that were already computed on a file that you can open for visualization and postprocessing purposes.

Read More##### Walter Frei June 30, 2015

Over the last several weeks, we’ve published a series of blog posts addressing the various domain and boundary conditions available for wave electromagnetics simulation in the frequency domain; as well as modeling, meshing, and solving options. In this blog post, I will tie all of this information together and provide an introduction to the various types of problems that you can solve in the RF and Wave Optics modules.

Read More##### Walter Frei December 26, 2013

One of the questions we get asked often is how to learn to solve multiphysics problems effectively. Over the last several weeks, I’ve been writing a series of blog posts addressing the core functionality of the COMSOL Multiphysics software. These posts are designed to give you an understanding of the key concepts behind developing accurate multiphysics models efficiently. Today, I’ll review the series as a whole.

Read More##### Walter Frei December 23, 2013

In our previous blog entry, we introduced the Fully Coupled and the Segregated algorithms used for solving steady-state multiphysics problems in COMSOL. Here, we will examine techniques for accelerating the convergence of these two methods.

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