How to Model Fundamental Sources in Enclosed Spaces

James Gaffney January 17, 2019

As the story goes, Archimedes was struggling with a case of suspected golden crown fraud. Whilst taking a bath, inspiration hit: Submerging an object displaces the same amount of water as the object’s volume, so he could expose any dilutions to the gold. Archimedes was so pleased, he yelled “eureka!” But would anyone have heard the now-famous shout? Using simulation, we can evaluate the acoustics of resonant and reverberant enclosed spaces, like bathrooms, and how they respond to fundamental sources.

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Erik Melin January 16, 2019

The goal of mesh adaptation is to modify the mesh to solve a problem more efficiently. We want to use as few elements as possible to obtain an accurate solution. Typically, we would like a coarser mesh in regions that are not very important and a more refined mesh in regions of interest. We might even consider anisotropic elements. As of version 5.4, the COMSOL Multiphysics® software includes enhanced tools to adapt a mesh. Let’s take a look.

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Prashant Srivastava January 9, 2019

Various machinery, such as engines, pumps, and turbines, employ components that transmit the load between the solid parts that are in relative motion. Common examples are piston rings, cams, gear teeth, and (of course) bearings. Often, these components are lubricated by maintaining an oil film between the two solid parts to minimize the friction and wear. In this blog post, we look at methods for modeling the fluid friction in lubricated joints.

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Kristian Ejlebjærg Jensen January 4, 2019

Engineers are given significant freedom in their pursuit for lightweight structural components in airplanes and space applications, so it makes sense to use methods that can exploit this freedom, making topology optimization a popular choice in the early design phase. This method often requires regularization and special interpolation functions to get meaningful designs, which can be a nuisance to both new and experienced users. To simplify the solution of topology optimization problems, the COMSOL® software contains a density topology feature.

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Chien Liu December 27, 2018

Carrier dynamics plays an important role in the transient behavior and frequency response of semiconductor devices. Here, we use two tutorial models of PIN rectifiers in the Semiconductor Module, an add-on to the COMSOL Multiphysics® software, to demonstrate the simulation of dynamical effects.

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Jinlan Huang December 20, 2018

Piezoelectric devices are widely used as sources to generate sound waves or receivers to detect acoustic signals. In applications such as ultrasound imaging and nondestructive testing, the same transducer can be used as a transmitter to send a source signal and receiver to detect echoes. Modeling these devices often requires transient analyses with time of flight as output. Let’s discuss how to use the COMSOL Multiphysics® software to model a piezoelectric device as both a transmitter and receiver.

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Chien Liu December 18, 2018

Traps are omnipresent in practical semiconductor devices. When modeling these devices, the Trap-Assisted Surface Recombination boundary condition adds the effects of charging and carrier capturing/releasing by surface or interface traps. Here, we examine a tutorial model of a metal-oxide-silicon capacitor (MOSCAP) to demonstrate how to use the feature in the Semiconductor Module, an add-on product to the COMSOL Multiphysics® software.

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Pawan Soami December 6, 2018

Composite materials are heterogeneous materials composed of at least two integrated components. Among the different types of composite materials, layered composite materials are quite common and are widely used for aircraft, spacecraft, wind turbine, automobile, marine, buildings, and safety equipment use cases. The Composite Materials Module, add-on to the COMSOL Multiphysics® software, includes built-in features and functionality specifically designed for studying layered composite structures. Fiber-reinforced plastics, laminated plates, and sandwich panels are a few common examples of layered composite materials.

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Ed Fontes November 29, 2018

There has always been a debate among engineers working with fluid flow about the suitability of finite element methods for CFD. Some engineers have a firm opinion about the superiority of finite volume methods compared to finite element methods. Is there a scientific support for this opinion? No, not in general. Different methods may be suitable for different problems. Let us see why.

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Walter Frei November 21, 2018

Did you know that the COMSOL Multiphysics® software allows you to have different discontinuous meshes in neighboring domains? Although the usual default behavior of the software is to use aligned meshes, there are times when we might like to have discontinuous meshes, such as for modeling conjugate heat transfer. Let’s delve deeper into this topic and see how these meshes can save us time and memory in our initial model development with just a little bit more effort.

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Jose Gregorio November 19, 2018

Global modeling of plasmas is a powerful approach to study large chemistry sets. In these models, the reactions are represented by rate coefficients. In particular, the rate coefficients of electron impact collisions depend on the electron energy distribution function (EEDF), which is often non-Mawellian and can be computed from an approximation of the Boltzmann equation (BE). Here, we explain how to create a global model fully coupled with the BE in the two-term approximation using the COMSOL Multiphysics® software.

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