## Simulating Viscous Fingering Using Equation-Based Modeling

##### David Kan December 18, 2013

A prospective user of COMSOL approached me about modeling viscous fingering, which is an effect seen in porous media flow. He hadn’t found a satisfying solution elsewhere, so he turned to COMSOL. I’d like to share with you some of my insight on how to go from idea to model to simulation by taking a “do-it-yourself approach” and utilizing the equation-based modeling capabilities of COMSOL Multiphysics.

### Fractals, Beyond Eye Candy

##### David Kan August 28, 2013

Fractals are those exotic mathematical entities whose geometric properties fall between integer dimensions (1D, 2D, 3D). Space-filling curves and bounded sets with infinite perimeters fall into this category.

### Multiphysics versus FEA

##### David Kan February 14, 2013

In a popular post from last year, I discussed accessing and manipulating the underlying equations in COMSOL. This blog post instigated reader comments, and most of the respondents appreciated, or even required, the ability to look at the mathematical model (i.e., equations) behind the physics. While considering this, I realized that there is more to the story, and with a little perspective, the community could benefit from further discussion.

### Is Fracking Safe? Scientists Turn to Simulation to Investigate

##### David Kan December 31, 2012

Hydraulic fracturing (popularly referred to as “fracking”) is a method to increase production of oil and gas from certain types of geological formations. It has been used for decades, but recently, as the practice has increased, fracking has become a controversial topic. I will avoid taking sides in this debate, but the fact that there is a conflict implies there needs to be a deeper understanding of the process and its effects.

### Equations: Who needs them?

##### David Kan September 28, 2012

Most of us take mathematical modeling for granted. After all, we’re taught physics and calculus almost hand-in-hand. But we owe a lot to the early pioneers like Isaac Newton, who demonstrated and strongly promoted interpreting natural phenomena through equations. Differential equations are especially useful since most things change as time marches on. Since we live in 3D space, partial differential equations (i.e., equations that express change in more than one “direction”) arise as the prominent tool to express continuum level […]

### User Tip: All about Icons

##### David Kan September 25, 2012

I give a lot of COMSOL workshops — about 20 so far this year. These are great events and they include hands-on minicourses, which allow me to connect with the audience. One topic that I often spend a few minutes on might surprise you: icons. The icons, especially those found at the nodes in the Model Builder, are packed with useful information. They’re easy to miss because they’re small, but knowing what they mean can be a big help.

### Moore’s Law for Solvers

##### David Kan September 12, 2012

At the heart of any simulation software are the solvers. Those are things that take geometry/mesh/physics to the computational results. While it’s convenient to think about solvers in terms of the type of study (think time-dependent, parametric, or eigenvalue), there is a hierarchy of solvers that are usually employed. And at the foundational level of any simulation — and for every iteration — there is a linear solver.

### Multiphysics Makes Single Physics Simulations Better

##### David Kan September 11, 2012

Coupled physics phenomena (like electrical heating, fluid structure interaction, and conjugate heat transfer) demand multiphysics, which I’ve written about previously in “What is Multiphysics?”. But what if you just have a simple analysis to do — one that has been simplified to the point where only a “single physics” (to coin a term) is considered? What benefits does multiphysics have for this?

### What Is Multiphysics?

##### David Kan September 4, 2012

If you’re a cynic (like I am sometimes), the term “multiphysics” might irk you. There’s only one set of physical laws, after all. There’s nothing “multi” about it. So what is multiphysics?

### The Secret Sauce in the Pipe Flow Module

##### David Kan June 22, 2012

We developed COMSOL Multiphysics to empower the engineering and science communities with state-of-the-art simulation tools. A key ingredient of this empowerment is flexibility. COMSOL users are already well aware of the full compatibility between various physics. This means you can put any (yes, really any) combination of COMSOL physics together. But that’s not the only way our multiphysics simulation tool is flexible.

### Version 4.3 Highlights — the Little Things

##### David Kan June 18, 2012

Version 4.3 was released just a few weeks ago, and it has already generated a lot of buzz. With three new products and many enhancements, there is a lot to sink your teeth into. Not the least of these enhancements are the “little things” — small usability improvements that can make life a lot easier (and modeling more efficient) for COMSOL users.