## Modeling Laser-Material Interactions with the Beer-Lambert Law

##### Walter Frei April 13, 2015

High-intensity lasers incident upon a material that is partially transparent will deposit power into the material itself. If the absorption of the incident light can be described by the Beer-Lambert law, it is possible to model this power deposition using the core functionality of COMSOL Multiphysics. We will demonstrate how to model the absorption of the laser light and the resultant heating for a material with temperature-dependent absorptivity.

Read More##### Phillip Oberdorfer April 9, 2015

Stirling engines, or heat pumps, are systems that are able to work on incredibly low temperature differences. In fact, some types of Stirling engines only need human body heat in order to operate. Here, we explore the dynamics of this interesting machine that you can build at home and demonstrate how to model it using COMSOL Multiphysics.

Read More##### Annette Pahl April 8, 2015

In a previous blog post, we introduced readers to different kinds of electron energy distribution functions (EEDFs) and their importance in plasma modeling. Today, we focus our attention on the Boltzmann Equation, Two-Term Approximation interface, demonstrating its use with an example from our Model Library.

Read More##### Fabrice Schlegel April 7, 2015

Today, we compare the Boussinesq approximation to the full Navier-Stokes equations for a natural convection problem. We also show you how to implement the Boussinesq approximation in COMSOL Multiphysics software and discuss potential benefits of doing so.

Read More##### Bridget Cunningham April 6, 2015

When an earthquake strikes, the force from its seismic waves can weaken the stability of buildings. By implementing seismic control measures, designers can enhance the flexibility of such structures as well as strengthen their safety levels. See how one research team used COMSOL Multiphysics to study the impact of base isolation systems and explore approaches to optimizing their performance.

Read More##### Brianne Costa April 3, 2015

As the burning of fossil fuels becomes a more pressing issue, manufacturers are introducing more fuel efficient cars to the market. One main contributor to fuel burn is the car’s aerodynamic drag. Complexly shaped, cars are very challenging to model and it’s difficult to quantify the aerodynamic drag computationally. The Ahmed body is a benchmark model widely used in the automotive industry for validating simulation tools. The Ahmed body shape is simple enough to model, while maintaining car-like geometry features.

Read More##### Bridget Cunningham April 2, 2015

In this blog post, we investigate syngas combustion in a round-jet burner using the Reacting Flow interface and the Heat Transfer in Solids interface. The results from this benchmark model are compared to experimental findings.

Read More##### Chien Liu April 1, 2015

Over half a century ago, Mark Kac gave an interesting lecture on a question that he had heard from Professor Bochner ten years earlier: “Can one hear the shape of a drum?” He focused on the (then undetermined) uniqueness of the set of eigenvalues given the shape of a vibrating membrane. The eigenvalue problem has since been solved and here we explore the “hearing” part of the question by considering some interesting physical effects.

Read More##### Bridget Cunningham March 31, 2015

Commonly used in the automotive industry, snap hooks are a type of fastener that involve the insertion of a hook into a slot. When designing snap hooks, it is important to analyze the forces required for the insertion of the hook as well as its removal. We can address this through simulation.

Read More##### Caty Fairclough March 30, 2015

Lightweight and portable washing machines are great to use in situations where you do not have access to traditional washing machines. Yet problems may occur when a varied distribution of clothing causes walking instability in these machines. We tested for walking instability during the spin cycle of a portable washing machine and used an active balancing method in an attempt to remove this instability.

Read More##### Walter Frei March 27, 2015

Often, the most tedious step of finite element modeling is subdividing your CAD geometry into a finite element mesh. This step, usually just called meshing, can sometimes be fully automated. More often, however, the careful finite element analyst will want to semi-manually create their meshes. Although this does require more work, sometimes there are significant advantages in doing so. In this blog entry, we will look at one of the key manual meshing techniques: the concept of geometric partitioning.

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