# COMSOL Blog

## Introducing the Ray Optics Module

##### Walter Frei | November 14, 2014

The release of COMSOL Multiphysics version 5.0 includes a new add-on module for electromagnetics modeling: the Ray Optics Module. This optional add-on module includes the Geometrical Optics interface, which can be used to model the propagation of electromagnetic waves when the wavelength is much smaller than the smallest geometric entity in the model. The Geometrical Optics interface includes a wide variety of features and optional settings and it is fully multiphysics capable.

### How Much Memory Is Needed to Solve Large COMSOL Models?

##### Walter Frei | October 24, 2014

One of the most common questions we get is: How large of a model can you solve in COMSOL Multiphysics? It turns out that this is quite tricky to answer decisively, so in this blog entry, we will talk about memory requirements, model size, and how you can predict the amount of memory you will need for solving large 3D finite element problems.

### Understanding Parallel Computing

##### Walter Frei | October 7, 2014

People are always asking how the performance of COMSOL Multiphysics® simulation software will improve on a parallel system, especially now that large multi-core desktop computers are relatively inexpensive and it’s easy to rent time on cloud services like the Amazon Elastic Compute Cloud™. It turns out, though, that it’s not always possible to get faster performance just by throwing more hardware at the problem. To understand why, let’s take a conceptual look at computers and the algorithms COMSOL® software uses.

### Modeling a Coil Heat Exchanger

##### Walter Frei | August 21, 2014

Coil heat exchangers are simple and easy to manufacture. Here, we consider an axially wound coil of copper carrying hot water that heats air inside of a circular duct. Since the geometry is almost invariant about the centerline, the model is solved in the 2D axisymmetric plane. Additional expressions are added to compute the temperature drop between turns of the coil, which greatly simplifies the modeling.

### Exploiting Symmetry to Simplify Magnetic Field Modeling

##### Walter Frei | July 14, 2014

Whenever modeling magnetic fields in steady-state, transient, or frequency domain with the AC/DC Module, we want to reduce the size of the model as much as possible to minimize the computational resources and time needed to solve the model. Today, we will introduce the three types of symmetry boundary conditions that you can exploit in your modeling and show how to use them.

### Getting the Most out of Client-Server Mode

##### Walter Frei | June 27, 2014

When using COMSOL Multiphysics on a Floating Network License, it is possible to use the Client-Server mode of operation to access remote computing resources for solving large models, while still using the graphics card on a local machine to display graphics. This can have some significant advantages, so let’s look at Client-Server mode in more detail.

### How to Integrate Functions Without Knowing the Limits of the Integral

##### Walter Frei | April 30, 2014

We all know that COMSOL Multiphysics can take partial derivatives. After all, it solves partial differential equations via the finite element method. Did you know that you can also solve integrals? That alone shouldn’t be very surprising, since solving finite element problems requires that you integrate functions. The COMSOL software architecture allows you to do a bit more than just evaluate an integral; you can also solve problems where you don’t know the limits of the integral! Here’s how.

### What Kinds of FSI Problems Can COMSOL Multiphysics Solve?

##### Walter Frei | April 14, 2014

One of the questions we get asked all the time is: “Can I use COMSOL Multiphysics for solving my fluid-structure interactions problems?” Of course the answer is yes, so let’s talk a little about the various fluid-structure interaction (FSI) modeling techniques. Along the way, we will introduce the add-on modules you will need for these various types of analyses.

### Modeling the Hydrostatic Pressure of a Fluid in a Deformable Container

##### Walter Frei | April 9, 2014

In a previous posting, we looked at computing and controlling the volume of a cavity filled with an incompressible fluid, which solved for the static deformation of a fluid-filled rubber seal. In that example, we did not explicitly model the fluid, but added an equation to solve for the pressure, assuming incompressibility of the fluid. Here, we will extend this approach and include the hydrostatic pressure of the fluid in the deforming container.

### Computing the Impedance of a Corrugated Waveguide

##### Walter Frei | March 25, 2014

It is well-known that you can use the RF Module to compute the impedance of lossless transmission line structures, such as coaxial cables of uniform cross section. But did you know that you can also compute an effective impedance for waveguides with non-uniform cross section? Let’s find out how!