# COMSOL Blog

## Simulating the Freeze-Drying Process

##### Alexandra Foley | August 1, 2013

When thinking about freeze-drying processes, I am reminded of astronaut food like the freeze-dried ice cream I tried as a kid. While this application of freeze-drying is important for preserving food being launched into space, there is also an incredible number of noteworthy applications that are used a little closer to home. Let’s take a look at the freeze-drying process, how it can be simulated, and some of the products and designs that rely on it to function.

### Analyzing Electrical and Thermal Conductance in a Contact Switch

##### Alexandra Foley | July 29, 2013

A contact switch is used to regulate whether or not an electrical current is passing from a power source and into an electrical device. These switches are found in many types of equipment and they are used to control, for example, the power output from a wall socket into a device when it is plugged in; the currents passing across the circuit board of a computer; or the electricity powering a light bulb when the switch is flipped on. Because of their […]

### Fatigue Prediction Using Critical Plane Methods

##### Mateusz Stec | July 22, 2013

Research on fatigue started in the 19th century, initiated following failing railroad axles that caused train accidents. In a rotating axle, stress varies from tension to compression and back to tension in one revolution. The load history is simple because it is uniaxial and proportional. Fatigue can then be evaluated with the S-N curve, also known as the Wöhler curve, which relates stress amplitude to a component’s life. In many applications we deal with multiaxiality and non-proportional loading. In this […]

### Acoustics Tutorial for Modeling Organ Pipe Design

##### Laura Bowen | July 19, 2013

The way the sound is shaped as it passes through the pipe of an organ is the result of a carefully calculated and intricate pipe design. Browsing through the Model Gallery, I came across a model of an organ pipe, and it happens to be a great acoustics tutorial for using the Pipe Acoustics, Frequency Domain interface in COMSOL Multiphysics. Let’s talk organ pipe design, and walk through how we can model it with multiphysics software.

### What Is the Doppler Effect?

##### Alexandra Foley | July 15, 2013

The Doppler effect, or Doppler shift, is the change in wavelength and frequency caused by the movement of an observer relative to the source. One of the most common ways we can experience the Doppler effect in action is in the change of pitch that occurs due to a moving sound source. You’ve probably experienced the Doppler effect when a fire truck or ambulance passes by with its sirens blaring. As the siren passes, the pitch suddenly drops as the […]

### Can You Use Heat Transfer to Predict Migration of Contaminants?

##### Alexandra Foley | July 10, 2013

The flow of fluid through a porous medium is usually described by Darcy’s Law. However, what if you wanted to look at a combination of fluid flow, heat transfer, and mass transport in a porous medium? Instead of using Darcy’s Law, which calculates an average linear velocity for fluid flow in porous media, the Navier-Stokes equations would be necessary in order to obtain accurate results. In addition, heat convection and conduction, as well as mass transport would need to be […]

### Simulating an Engine Governor, the Spring Loaded Centrifugal Governor

##### Alexandra Foley | July 5, 2013

We’ve probably all seen centrifugal force in action in one way or another, whether it be riding on a merry-go-round as a child, spinning a bucket of water upside and observing as the contents hug the insides of the bucket, or watching mud spinning off of a turning tire. In addition to making dizzying carnival rides, this force can be used in the design of many mechanical applications, where it is harnessed to control a variety of effects. One such […]

### Aircraft Landing Gear Mechanism Analysis

##### Fanny Littmarck | July 3, 2013

Aircraft rely on landing gear in order to taxi, take off, and land. The landing gear of your average commercial airplane consists of a shock-absorber cylinder and piston, and a pair of tires. Intuitively, the shock-absorber experiences stresses as the landing gear touches the ground — but how much? In order to design a landing gear mechanism that can withstand many landings, and to determine when it’s time to swap out an old one, we can perform a multibody dynamics […]

### Simulating Plate Heat Exchangers

##### Laura Bowen | June 26, 2013

It’s not always obvious what a major role temperature control plays in modern technology, as the interchange happens in the background. Plate heat exchangers, made up of successions of metal plates and various coiled pipes, regulate and manipulate temperature, and they get the job done quickly — thanks to an active surface that is large with respect to their volume.

### A Multidisciplinary Approach to Electronics Design

##### Andrew Griesmer | June 24, 2013

Sharp is a powerhouse in the electronics industry, involved in televisions, liquid crystal displays, LED lighting systems, solar cells, multi-function business machines, and many other electronics-based products. One of a global network of Sharp R&D laboratories, Sharp Laboratories of Europe (located in Oxford, England), has been busy researching and developing LED lighting, display technology, microfluidic lab-on-a-chip, and energy systems for incorporation into Sharp’s products.

### Thermal Analysis Measures Blistering Heat

##### Laura Bowen | June 18, 2013

If you roast a turkey for dinner and you need to check the temperature, the technology exists to find it. But what happens if the temperature is so hot that a consumer-grade thermometer, or any man-made device, really, would instantly melt and be destroyed? This might not be a common occurrence in your kitchen, but it is a real concern in blast furnaces, where temperatures can reach close to 1,500°C. Simply guessing is far from safe. Luckily, by simulating with […]