How to Use the Beam Envelopes Method for Wave Optics Simulations

Yosuke Mizuyama January 8, 2018

In the wave optics field, it is difficult to simulate large optical systems in a way that rigorously solves Maxwell’s equation. This is because the waves that appear in the system need to be resolved by a sufficiently fine mesh. The beam envelopes method in the COMSOL Multiphysics® software is one option for this purpose. In this blog post, we discuss how to use the Electromagnetic Waves, Beam Envelopes interface and handle its restrictions.

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Chandan Kumar January 4, 2018

A sphere slightly lighter than water is dropped into a small liquid-filled beaker. How do you model the resulting shape of the water surface and the motion of the sphere as it floats on the surface? In this blog post, we demonstrate how to model this system in the COMSOL Multiphysics® software. Although we are considering the case of a small sphere, the technique discussed here can be applied to other larger shapes as well.

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Ed Fontes December 26, 2017

You can easily describe composition- and temperature-dependent fluid properties using the thermodynamic properties database, available as of version 5.3a of the COMSOL Multiphysics® software. For reacting systems, the database computes enthalpy of formation and enthalpy of reaction. For fluid flow and heat and mass transfer, the database can compute viscosity, density, heat capacity, thermal conductivity, and diffusivity of liquids and gases. For systems with several phases, the thermodynamic properties database computes the composition of the phases at equilibrium.

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Hanna Gothäll December 19, 2017

In Part 2 of our blog series on how to model irregular shapes in the COMSOL Multiphysics® software, we focus on how to create a surface of an irregular shape based on elevation data stored in various formats such as text, an image, or a DEM file. This approach is best suited for data where the height (or elevation) is a function of x- and y-coordinates.

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Phillip Oberdorfer December 15, 2017

The physics behind filling a water balloon seem simple at first glance, but involve a rather complex interplay of fluid flow and a nonlinear hyperelastic material. Fortunately, it is easy to set up and solve this type of model in the COMSOL Multiphysics® software. Let’s see how…

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Amit Patil December 6, 2017

Measurements and units make our professional and personal lives orderly and systematic. Different unit systems have been used over time, but today there are two dominant systems: the metric and English unit systems. What happens when both unit systems are used for the same application? In this blog post, we will shed light on two historical disasters brought about by the use of different unit systems and highlight unique features of the COMSOL Multiphysics® software for handling different unit systems.

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Uttam Pal December 4, 2017

On a bright evening in 1669, Professor Erasmus Bartholinus looked through a piece of an Icelandic calcite crystal he had placed onto a bench. He observed when he covered text on the bench with the stone, it appeared as a double image. The observed optical phenomenon, called birefringence, involves a beam of light that splits into two parallel beams while emerging out of a crystal. Here, we demonstrate a modeling approach for this effect.

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Walter Frei November 30, 2017

To fillet or not to fillet, that is the question (that can bedevil the multiphysics analyst). When building finite element models, sharp edges can lead to local singularities and fields that are nonconvergent with mesh refinement. Rounding off these sharp edges by adding a fillet avoids this singularity. As it turns out, in many multiphysics models, these sharp edges and the resultant singularities do not necessarily negatively affect the results. Let’s find out more.

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Rasmus Karlsson November 27, 2017

Wet chemical etching is used to form patterns on surfaces, with applications including the production of integrated circuits, MEMS devices, and pressure sensors. This process has been around for hundreds of years, and was a favorite method of Old Master Rembrandt van Rijn. The optimization of chemical etching was historically a matter of trial and error, but in this blog post, we’ll show how to model the process in the COMSOL Multiphysics® software.

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Ajit Bhuddi November 8, 2017

Suppose you have a very long system with a constant cross section: a fluid-filled pipe. Modeling this system is computationally expensive and time consuming. Using a guided wave propagation approach, you can model a cross section of the system and compute the guided waves along it. You can represent such waves by means of dispersion curves. Here, we discuss a coupled analysis considering air and water as the internal fluids. We also analyze the system dynamics using dispersion curves.

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Mats Danielsson November 2, 2017

In structural mechanics, there may be situations when you want to implement your own material model. The COMSOL Multiphysics® software gives you the option to program your own material model in C code. The compiled code can then be called from the program using the External Material feature. Here, we demonstrate how to implement an external material model and then use it in an example analysis.

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