Fluid

Alexandra Foley | July 23, 2013

There are many different forces that can induce flow in fluids, such as kinetic energy, pressure gradients, concentration gradients, and many more. In natural systems, one effect that can initiate fluid flow in a still fluid is a change in density. This density change will result in a change in the fluid’s buoyancy, thus inciting flow as the denser fluid sinks and the less dense, buoyant, fluid rises. You’re probably most familiar with these changes in density occurring due to […]

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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 […]

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Valerio Marra | July 2, 2013

Of all boats, I find sailboats to be the most fascinating, especially when sails are their only means of propulsion. Kinetic energy is transferred from the wind to the sails, which results in a lift force that balances drag forces and allows the sailboat to move through the water. We are all familiar with the parts of a boat above the waterline: deck, spars, sails, and the rudder used to turn the boat (figure 1c). Not everyone pays attention to […]

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Alexandra Foley | June 17, 2013

The fact that oil and water don’t mix is something that you are probably all familiar with. At one point or another, you’ve most likely noticed what happens when you shake a bottle of say, Italian salad dressing, and the liquids mix momentarily, only to become separated again within seconds as oil bubbles rise to the surface. Creating a simulation describing how these two immiscible fluids interact is a great way to introduce computational fluid dynamics (CFD) applied to two-phase […]

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James Ransley | May 16, 2013

Vacuum technology has many important applications, from semiconductor device and MEMS fabrication, to vacuum coatings for corrosion protection, optical films, and metallization. The new Molecular Flow Module provides vacuum engineers with previously unavailable tools for modeling gas flows within vacuum systems.

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Daniel Smith | May 2, 2013

Graphene can be created by way of thermal decomposition at high vacuum. In order to design and optimize these high vacuum systems engineers might look to simulation, but there are currently not many modeling tools that are up to the task. Let’s have a look at how vacuum systems are relevant to graphene production, why you should simulate them, and how.

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Bjorn Sjodin | April 16, 2013

Vacuum is naturally associated with the hostile environment of deep space. To achieve such an environment in an artificial setting here on Earth is a very challenging task, and it turns out one cannot even come close to the low pressures of an interstellar vacuum. It is at these low pressures that molecular flow occurs.

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Jennifer Segui | April 11, 2013

If you enjoy ketchup with your food, there’s a good chance you’ve experienced what we’ll call here the all-or-nothing ketchup quandary. You know, that moment when you reach for a new glass bottle of ketchup, remove the cap, and turn the bottle practically upside down — and then nothing happens. Intuitively you shake or tap the bottle, and then suddenly your food is completely coated in ketchup (unless your reflexes are really good, of course). In this blog post we […]

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Cinzia Iacovelli | April 5, 2013

Have you ever noticed how water can flow through rocks and leave a trace of its passage by covering the surface with a patina, like white stripes? The whole process is quite complex but can roughly be explained by breaking it down into two coupled effects: gravity and chemical reactions. Gravity causes the water to infiltrate through discrete fractures (hard rocks) or pores (sedimentary rocks), until it charges the groundwater supply below to a point where excess water will surface […]

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Valerio Marra | March 13, 2013

I love trees and my favorite is definitely the ficus, all varieties included. A few weeks ago I had the chance to admire a stately ficus microcarpa (see figure below). What struck me above all were its aerial roots. Roots are designed to absorb water and nutrients, sustaining the tree and synthesizing substances responsible for its growth. A thought crossed my mind right away: the shape of those roots and the way they coalesce have surely been optimized by Mother […]

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Alexandra Foley | March 8, 2013

Water purification is the process by which chemicals, contaminants, and sediments are removed from dirty water to make it clean, and there are many processes through which this can be done. What you might not know, is that ozone molecules can be used as a means of disinfection in the purification process. “Ozonation” has been used to purify water, kill germs and bacteria in food, and even get rid of bad smells. Not only does ozonation provide clean water without […]

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