I’m Luiz Fernando Silva and This Is How I Mesh

Luiz Fernando Silva, Professor at Federal University of Rio de Janeiro.

Luiz Fernando Silva, Professor at the Federal University of Rio de Janeiro.

I was born and raised in Rio de Janeiro, Brazil, and I am the eldest of three boys. We lived in the north region of the city, called Tijuca, which is very close to America’s largest urban forest, Tijuca’s Forest. When I was six years old, I wanted to be a soccer player like most of the boys in Brazil. However, my legs didn’t agree with me when during the games I would get hit by the ball and stumble while running. After this, I accepted that being a soccer player would not be my specialty. In fact, I was terrible…so back to the books! In all, it was not hard to figure out that I always liked technical and science subjects.

I started my bachelor’s degree in chemical engineering at the Federal University of Rio de Janeiro (UFRJ). During the second year of the course, I joined a research laboratory as a scientific intern. The term “scientific intern” is a Brazilian government program designed to encourage young students to learn more about science. So I joined the Thermo-fluid-dynamics laboratory and learned the basics of scientific programming and numerical methods applied to hyperbolic equations. I realized that I wanted to learn more about transport phenomena and numerical methods. Therefore, as soon as I finished the bachelor course, I registered for a post-graduation course in the same laboratory.

The topic of my Ph.D. thesis was the implementation of polydisperse multiphase flows using moments method because at that time commercial CFD codes did not have this modeling approach implemented. At first, the task involved writing an in-house code from scratch, but I soon realized the effort of meshing and numerical methods would be considerable. Instead, I checked the release of a new open-source CFD code named OpenFOAM and as I studied the code I realized I could focus on the implementation of the multiphase modeling. After all, the meshing, numerics and post-processing were already included on the software. This is the story of how I started using OpenFOAM.

I assumed a professor position at the Federal University of Rio de Janeiro one year after my Ph.D. defense. From that time, I assumed several disciplines, mostly related to Transport Phenomena and Numerical Methods, and had many undergraduate students. I’ve been working with multiphase flow and general CFD development and plan to focus on compressible flows and optimization moving forward.

My former Ph.D. supervisor and I noted that an open-source approach to the CFD market would be important and prominent in Brazil, especially high quality services which include CFD simulations and development using OpenFOAM. Considering this, and together with former students, we founded Wikki Brasil in 2013 with partnerships with Wikki and Pointwise. Wikki Brasil was founded within the UFRJ Company Incubator program which is an incentive for starting companies in Rio de Janeiro. It is an important support helping Wikki Brasil face the Brazilian economic and political crisis nowadays.

As a professor at a federal university, my role at Wikki Brasil is only as a non-administrative associate. This means I don’t actually work on company projects, but I can help instruct Wikki Brasil associates as an external consultant. Considering this, I am very proud to be part of Wikki Brasil.

  • Location: Rio de Janeiro, Brazil
  • Current position: Professor at the Federal University of Rio de Janeiro
  • Current computer: MacBook Pro (Retina, 13-inch, Late 2013) 2.4 GHz Intel Core i5 and 8 GB 1600 MHz DDR3 (El Capitan) and a desktop with Gigabyte X99, Intel Core i7 5820K (3.30 GHz), 32 GB RAM DDR4 2400 MHz, Nvidia GeForce GTX 970 4 GB GDDR5, 120 GB SSD and 2 TB HD (CentOS 7).
  • One word that best describes how you work: Dedicated

What software or tools do you use every day?

I use a MacBook Pro (El Capitan) on a daily basis as my productive computer. I use it most of the time for general tasks like accessing the internet and e-mail, as well as reviewing and writing material. The applications I use most often are:

  • Macports to install and maintain Linux command-line applications and libraries.
  • Safari and Google Chrome for internet and Apple Mail and Gmail (web interface) for my e-mails.
  • Adobe Acrobat Reader (activating the Comment option) or Skim for reviewing papers and documents.
  • LaTeX (MacTex package) and TeXnicle IDE for writing technical documents and presentations.
  • Apple Calendar to keep my appointments organized, Things to organize my to-do list, Evernote to save and organize all my notes and bookmarks. I use Mendeley Desktop to keep articles and reference material organized.
  • I use several cloud services for data synchronization like Dropbox, iCloud and Owncloud.
  • I use Skype and WhatsApp (on my iPhone) to communicate with my friends and colleagues.
  • I also use Twitter and Facebook to stay up to date with CFD news and related material.
  • And lastly, Spotify is always on with my Rock Classics playlist.

I have installed Pointwise, OpenFOAM, foam-extend and ParaView on both my MacBook Pro and Linux desktop. The MacBook is my first choice for small projects. For serious simulation and code development, I connect remotely to my Linux desktop from the MacBook using ssh. For code development, I use vim (Linux and MacOS) and TextMate (MacOS) with gcc and clang compilers.

What does your workspace look like?

luizsilvaworkspace

I work at the School of Chemistry at the Federal University of Rio de Janeiro. It is located on the E Block of the Technologic Center of the university. Professors’ offices on E Block are somewhat distant from the research laboratories. Considering this, I recently left my old office and moved to a small office inside the CFD Laboratory. My motivation was mainly to be closer to students and, despite the smaller size, I really enjoy working at the new office.

The CFD Laboratory (LabCFD) is administered by four professors, including me. We have several Ph.D., master’s and under-graduated students dealing with several topics related to CFD and transport phenomena. The laboratory also has experimental activities that provide data to validate simulations. There are several pieces of equipment there, but I would say that the most important of all is broken at the moment – the coffee machine. Just kidding…

My office is small but I find it very cozy. I have scattered some gifts from places I have traveled all over the place. My desk is minimalistic as I keep only essential office and computer material within reach. I use a 29” widescreen monitor connected to both my MacBook Pro and Linux computer. I can use the wide area of the monitor to organize the working application windows side by side and let the MacBook screen be used for e-mail, calendar and to-do list programs. I also chose this configuration instead of multiple monitors mostly to maintain a simple and clean desk.

What do you see are the biggest challenges facing CFD in the next 5 years?

Transport phenomena alone is not an easy subject and requires a lot of dedication to understand the theory and how to use it for practical cases. The same applies to numerical methods applied to fluid flow, coupled equations, and meshing procedures. Add scientific computing (parallel processing, data communication, scientific visualization, etc.) to the formula and you might have the basis for CFD theory. CFD is a multidisciplinary area and it is not easy to keep yourself up to date on all subfields. There is a need for long term dedication and some effort studying the theory.

It may seem a bit tendentious for a professor, but I am quite sure education will be a challenge. From what I see, many engineers use simulation tools as “automagical” solutions to their problems. After all, it is easy to enter some parameters and promptly get a solution. When starting to use CFD, it is easy to get lured by all colors and pretty pictures. I recognize that the accessibility of a user interface is important, but people are heavily relying on it to solve complex problems. Thus, the challenge of education is to provide a balance of software and CFD knowledge.

In general, the engineering bachelor degree may not be enough to train a CFD specialist. Usually, under-graduate students have their first contact with CFD using commercial software and simple cases. Further training and personal effort is also necessary. What worries me is that the fast CFD popularization is providing button pushers without motivation to understand what is beneath and criticize the solution.

As I was writing this post and I found that Darrin Stephens has a similar opinion.

What are you currently working on?

As a professor, I am supervising some Ph.D. and master’s students working on several subjects related to CFD modeling and development. The majority of themes are related to polydisperse multiphase flows. To pick one example, one of my Ph.D. students is finishing his research project on hydrate formation modeling using a multivariate population balance approach coupled with a multiphase flow code in OpenFOAM.

I have a meshing related task scheduled for the next few weeks where I will generate a grid for a cyclonic valve which has a very complex geometry. At the moment, I am cleaning the geometry using some solid modeling hints and I am already expecting to put some effort on the meshing procedure. In other words, fun time!

What would you say is your meshing specialty?

I don’t think I have a meshing specialty, but rather I am meshing enthusiastic. Let me explain.

I began playing with meshes a long time ago with ANSYS ICEM CFD and found it a very difficult task. At that time, there were no good manual tools for blocking strategies and vertices associations, and Octree was “automagical” for a beginner. After that, I began playing with OpenFOAM and meshing tools available within, i.e., blockMesh. That was the time when I was pretty sure meshing was not my thing.

It took me a long time before I dealt with serious meshing again. I started using Pointwise for very simple meshes and it was surprisingly easy to use. Once you understand the relation of connectors and domains and how to control every aspect of these entities (using Dimension, Distribute and Solve panels, for instance), you gain the confidence to mesh more complex geometries. This is just one step forward to deal with more complex meshing tools like extrusion, T-Rex and Overset techniques.

Despite having a preference for structured meshes, I also work with unstructured meshes for general CFD cases. At the moment I’ve been playing with Pointwise V18 and unstructured meshes (Advancing Front Ortho algorithm with triangles and quads) coupled with T-Rex. In the end, I can’t say I have a mesh specialty as I am still learning several aspects of meshing. To be honest, I have found that meshing is quite fun.

Any tips for our users?

I had the opportunity to attend a Pointwise standard training course at the company’s headquarters in Fort Worth. The training course was very important to begin understanding the Pointwise methodology for mesh generation and start my own projects. At the same time, I was able to meet several Pointwise employees: Travis Carrigan, John Dreese and Claudio Pita from the technical team, and Heather McCoy and Rick Matus from the sales team. So, my first tip is to keep in touch with Pointwise and the team of distributors. They can (and will) help you to use Pointwise and improve your knowledge on meshing strategies with the software.

In addition, if you can’t attend the training, there are several tutorials and webinars available on Pointwise’s channel on YouTube. The beginners may find videos explaining different aspects of the software, from basic meshing to examination of mesh quality. Even if you are an expert user, you can find more advanced material presented in the webinars and webcasts. So, this is a tip for Pointwise users of different levels of expertise. Go get some popcorn and watch the videos.

For a last tip, several details (even small ones) that can improve your mesh are described in the manual. Thus, consider it for serious power when meshing.

If you are from Brazil and want to know about Pointwise, get in contact with Wikki Brasil.

What project are you most proud of and why?

None of my work projects come to my mind when I think of an answer to this question. Instead, I think of all the students I have supervised and their personal and professional evolution. From the first steps using C++ and numerical methods, to fully coding a complex OpenFOAM solver, until realizing they are actually enjoying all of it, their evolution is notable. In the end, it is not hard to see that they are now much more proficient in specific topics than I am (or was). This is what I am proud of most of all.

What CFD solver and post-processor do you use most often?

I use OpenFOAM and foam-extend for my research projects and to prepare teaching material. Not often, I also use ANSYS Fluent or CFX due to some student or client restriction. For post-processing I use ParaView and gnuplot.

Are you reading any interesting technical papers we should know about?

No, not really. At this time I am studying compressible flow theory in order to apply it for supersonic equipment for gas separation. As a chemical engineer, supersonic flows are not usual and so the theory is not approached during bachelor’s studies. So I am getting back to basic steps and increasing the complexity as study advances. The references I am using are:

  • Fox, R. W., McDonald, A. T. and Pritchard, P. J., Introduction to Fluid Mechanics, John Wiley & Sons, 6th ed., 2004. (Chapters 11 and 12)
  • Oosthuizen, P. H. and Carscallen, W. E., Introduction to Compressible Fluid Flow, CRC Press, 2nd ed., 2014.

If you have any tips about this subject, would you please leave a comment? Thank you in advance!

Do you plan on attending any conferences or workshops this year?

I am still depending on the release of funds from projects and research agencies in order to plan these activities. I would like to attend the OpenFOAM Workshop to keep up to date with recent news and developments. In addition, I would like to attend the next Pointwise User Group Meeting.

Also, I have gathered a team to organize the Brazilian OpenFOAM User Group Meeting in 2017 which will take place in Rio de Janeiro. I am on the organizing committee of Brazilian Congress of Computational Fluid Dynamics (CBCFD) and we will start to organize the congress this year, despite happening in 2018. If you want to know how the 2016 edition was, click here.

What do you do outside the world of CFD?

Besides the CFD world, I enjoy spending time with my family and friends. My mother lives close so I visit her very often. I also enjoy taking a long walk with my dog, Sherlock, and my wife. Rio de Janeiro is a wonderful city and the weather is perfect for outside activities.

I have been a video game fan since I was a boy. Considering this, I have evolved from an Atari system to PS3. Even so, I am so busy at the moment that there is a long period of time when I don’t play anything. I consider an exception only when my goddaughter visits me. She enjoys playing PS3 games and wants (requires) me to play with her. During some pauses, I usually play indie games on iOS.

I have a collection of TV series and movies to watch on Netflix. I usually like to watch all seasons/episodes of each TV show at a time, but recently I have been breaking this rule. I am following Neil deGrasse Tyson in Cosmos and watching the last season of Black Mirror. In addition, I am also watching the Sherlock TV series. And before you ask, no, I am not following the Game of Thrones series. Instead, I am reading the fourth book of the collection.

Speaking of which, I also have a book collection. Most are historical romances, such as The Pillars of the Earth and Saxon Chronicles, but recently I have been interested in science history and scientific facts about unsolved mysteries.

What is some of the best CFD advice you’ve ever received?

Uncle Ben, from the Spider-man comic books, once said, “With great power comes great responsibility.” He didn’t know at the time, but he was talking about CFD.

If you had to pick a place to have dinner, where would you go?

Rio de Janeiro is a big city, with several options for restaurants. So, this is a difficult question. Considering that I really like seafood, I know a restaurant that serves a varied menu including many dishes of fish, shrimp, crab, lobster and more. Really, the menu is so diverse that you may even find a sushi bar there (yep, Japanese food is included). The restaurant is called “Casa da Ostra na Brasa” which means Grilled Oyster House. Still, be aware that it is not the cheapest restaurant (approximately 22.00 U.S. dollars), but did I mention it is all-you-can-eat?

About Travis Carrigan

A Pointwise engineer helping other engineers solve their meshing problems.
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