Non-Newtonian Fluids, Between Solids and Fluids

Valerio Marra | January 22, 2013

One of my favorite sitcoms is “The Big Bang Theory”, thanks to its focus on physics. From time to time they run funny experiments that can be easily arranged at home, causing me to wonder if I know the physics that are at work. One of my favorite episodes is when they fill the cone of a speaker with a suspension of starch in water. Instead of spattering around, the suspension starts to dance because it behaves more like a […]


Valerio Marra | January 14, 2013

We have written several blog posts on postprocessing already, but none detailing postprocessing for CFD. Postprocessing has always been an important part of my teachings, as you learn how to use COMSOL Multiphysics while also gaining insight into the physics at hand. I would like to share with you part of the classwork I proposed when teaching a CFD training course not long ago.

Valerio Marra | December 21, 2012

The winter here in Boston has been very mild so far. A few days I would even have liked to have the air conditioning back on. I checked in with one my colleagues to check if he was having an equally hard time staying cool, and to my surprise, he was not. Why? He had constructed a make-shift air conditioner (A/C).


Valerio Marra | July 25, 2012

As Program Chair of the COMSOL Conference in Milan this year, I’m excited to announce that Marco Cati will be a keynote speaker presenting his design and optimization of ultrasound imaging systems at his company, Esaote S.p.A..


Valerio Marra | July 11, 2012

I know, I know… I should spend the weekend relaxing. But every place I visit offers me a variety of natural phenomena I wasn’t aware of and, as an engineer and a multiphysics enthusiast, I can’t help but sit in the sun jotting down a list of the physics involved – possible coupling mechanisms, boundary conditions, materials, and so on (we talked about stereotypes attached to engineer on our


Valerio Marra | February 10, 2012

I was reading Fanny’s blog post about the call for papers and it reminded me of my duties as program chair of the COMSOL Conference 2012 that will be held in Milan, Italy. I had gotten distracted. At the time I was working on a two-phase non-isothermal flow simulation and I was lost in my train of thought… “How to correctly represent volume forces? Is it ok to use the Boussinesq approximation? Is this mesh fine enough? Am I using […]


Valerio Marra | January 3, 2013

Nature is full of counter-intuitive phenomena; I’m fascinated by everyday examples like the one we talked about this summer, sinking bubbles in a pint of Guinness, but I have to say that engineering has its fair share of such examples too. The concept of heat exchange in coaxial pipes struck me as a student, as it showed me the relentless tinkering attitude typical of engineers wanting to optimize their design. In this kind of heat exchanger both streams, hot and […]


Valerio Marra | July 30, 2012

All this talk about piezoelectricity got me thinking about how surrounded we are by everyday items whose performances rely on this physical process. Examples include inkjet printers, speakers, electric guitars, and ultrasound imaging systems. With so many different common objects utilizing this phenomenon, it may lead you to wonder: what is piezoelectricity?


Valerio Marra | July 19, 2012

Remember those retro desk ornaments of the 1960’s, those lamps filled with colorful wax that began to move when the lamp was lit? I’m talking about lava lamps, or as I like to call them, “Rayleigh–Taylor instability machines”. They may not be popular among today’s youth, but I still own one and I thought it would be interesting to look beyond the dyed blobs of wax and observe the physics involved in lava lamps.


Valerio Marra | June 7, 2012

The early bird abstract submission deadline for the Milan conference is in two weeks. By uploading your abstract by June 22nd you will receive a reduced registration rate.


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