## Simulation Apps: How to Add a File Menu with Save Options

##### Andrew Griesmer August 25, 2015

When a user running your COMSOL app finds a particularly interesting set of results, they might need to save their app so they can come back to it later. Without save options, you’d have to re-run the simulation later with the input parameters they gave you. That would be very inefficient and defeat the purpose of creating simulation apps. Today, we’ll show you how to add a file menu with save options in your app.

### How to Implement a Point Source with the Weak Form

##### Chien Liu August 24, 2015

Today we continue our discussion on the weak formulation by looking at how to implement a point source with the weak form. A point source is a useful tool for idealizing the situation where a source is concentrated in a very small region of the modeling domain. We will find that it is very convenient to set up such a point source using the weak form.

### Studying Salt Damage to the World’s Crumbling Buildings

##### Brianne Costa August 20, 2015

We sometimes hear of tourists getting into trouble for carving their initials into the walls of the Coliseum in Rome and other famous structures. However, the more serious damage to this architecture is caused by something else entirely — salt. Transported by wind and water droplets, and even found in some building materials, salt is a powerful mineral that can cause a building’s façade to crumble and break. Researchers studied this effect to better predict salt’s behavior and prevent damage.

### Analyzing Mutual Inductance in Different Coil Arrangements

##### Brianne Costa August 19, 2015

Have you ever noticed that being around a happy, enthusiastic friend makes you feel happy too? You can look at mutual induction in a similar way: A current flowing through one circuit creates a current in a nearby circuit. Mutual inductance measures the amount of change required for this effect to take place. Here, we explore using simulation to compute the mutual inductance in different wire coil arrangements.

### How to Build an App from a COMSOL Multiphysics Model

##### Andrew Griesmer August 18, 2015

The Application Builder is an easy-to-use tool built into COMSOL Multiphysics. After watching the 10-minute video below, you will know how to build a functioning app from a model — and be on your way to building your own customized simulation apps.

### Simulating a MEMS-Based Pressure Sensor Inspired by a Cave Fish

##### Caty Fairclough August 17, 2015

Many aquatic vehicles use power-hungry active sensing methods to detect and identify objects within an oceanic environment. In order to find an energy-efficient alternative, a team of researchers from the PSG College of Technology in India used numerical simulation to investigate a pressure sensor design inspired by a blind cave fish. In this blog post, we’ll take a closer look at this passive MEMS-based pressure sensor.

### App: Measuring the Diffraction Efficiency of a Wire Grating

##### Bridget Cunningham August 13, 2015

Diffraction gratings are often used as a tool for bending and spreading light in optical instruments. Analyzing the diffraction efficiency of such optical components is important, as this can affect the instrument’s performance. Simulation offers an efficient way for testing various grating designs to achieve an optimal configuration. By creating a simulation app, you can further expedite this process, extending simulation capabilities to a wider audience. Our Plasmonic Wire Grating Analyzer demo app highlights this approach.

### Happy Birthday, Erwin Schrödinger

##### Fanny Littmarck August 12, 2015

Erwin Schrödinger is the man behind the famous Schrödinger wave equation that is used to predict the future behavior of a dynamic system in quantum mechanics. Today would have been Schrödinger’s birthday, had he still been alive. Let’s celebrate his birthday with a look at some of his accomplishments.

### Using General Extrusion Operators to Model Periodic Structures

##### Walter Frei August 11, 2015

In the course of building multiphysics models, we often encounter situations in which the solution to one physics is periodic — or very nearly so — while the solutions to other physics of interest are nonperiodic. If we know this ahead of time, it is possible to exploit the periodicity to reduce computational requirements. Here, we will demonstrate how to accomplish this using the General Extrusion component couplings in COMSOL Multiphysics.

### NREL Enhances Biofuel Conversion Processes with Simulation

##### Bridget Cunningham August 10, 2015

Biofuels are recognized as a valued source of renewable energy, with applications ranging from heating buildings to powering transportation. Increasing the availability of these fuels requires an understanding of the processes behind biomass conversion. With the help of COMSOL Multiphysics® simulation software, researchers at NREL are seeking to optimize such processes, making biofuel conversion more efficient and cost-effective.

### Avoiding Ship Hull Corrosion with ICCP and Simulation

##### Caty Fairclough August 6, 2015

Avoiding corrosion in a harsh ocean environment often requires the use of cathodic protection methods. These utilize different tools, such as sacrificial anodes or impressed currents, to help maritime-based industries stay afloat. One such system, impressed current cathodic protection (ICCP), mitigates corrosion by applying an external current to a ship hull. The efficiency of this method depends on factors such as the use of a coated propeller. Here, we use simulation to investigate how coating a propeller affects ICCP efficiency.