I was born in Kutina, a small town in Croatia. The region, Moslavina, is well known for its vineyards and škrlet, a white grape variety. Since I was very little I have been a Formula 1 enthusiast. In fact, I loved the sport so much that, after finishing secondary school in my hometown, I decided to study engineering at The Faculty of Mechanical Engineering and Naval Architecture in Zagreb. I graduated in 2014 under the supervision of prof. Hrvoje Jasak, one of the founders and principal developers of OpenFOAM. I started a Ph.D. in numerics the same year and have been a part of his CFD team ever since. I can say that I’m the meshing expert/artist on our team since the guys often ask me to create meshes for them.
- Location: Zagreb, Croatia
- Current position: Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Assistant
- Current computer: Its name is Matthew – CPU Intel Core I7-4820K CPU @ 3.20GHz, 32GB RAM, X79 Extreme4, Ubuntu 16.04 LTS
- One word that best describes how you work: Studious
What software or tools do you use every day?
I read the news as soon as I get to my office and I use Google Chrome as my browser. I’m a loyal Google app user. Most of my work is CFD – my holy trinity for putting simulations together consists of Pointwise for geometry preparation and meshing, foam-extend-3.2 or 4.0 for calculations and ParaView for postprocessing. I use Latex for writing papers and making presentations and vim for code editing.
But my absolute favorite software is our team’s MediaWiki. It’s a private website which we use for everyday communication, writing progress reports, tracking what our students are doing, sharing interesting papers, books, etc. It’s like a business social network and is extremely easy to edit and browse through.
What does your workspace look like?
My office is located on the 8th floor of the southern Faculty building. It is equipped with modern black wooden furniture and comfortable office chairs. The walls are covered with framed jet engine posters (Chair of Turbomachinery!). My desk is under a window and it overlooks the national television building and Sava River. There is always some seasonal fruit in a bowl, because I like to snack all the time, and a water bottle. I usually have a bunch of notebooks spread across my desk with code organisation notes, calculations, and simulation plans. There is also a Ferrari Formula 1 miniature with the number 7 on it to remind me why it all started. The rest is very ordinary: screen, keyboard, mouse, pens (my most used one is the 4 colour Pointwise pen), sticky notes, paper clips…and the Pointwise accelerators mousepad of course!
What do you see are the biggest challenges facing CFD in the next 5 years?
During the summer schools, which we organise to provide support for experienced OpenFOAM users, I have met many scientists and students working on extremely challenging physics. The problems require huge meshes and complex models which are not easy to solve. So, the future should bring more efficient and faster solvers to tackle such demanding large-scale simulations. We want a minimal amount of operations while achieving fast convergence.
What are you currently working on?
I’m mostly involved in my Ph.D. project where I’m working on implicitly coupled algorithms. foam-extend-4.0 has great capabilities for writing block coupled solvers which provide faster convergence compared to the conventional segregated approach. But, as it is a new technology, there are still many unknowns. Most of us know how to set up a solver based on the SIMPLE/PISO algorithm in a few seconds, and it works. I’m trying to establish a “How to” and “Best practice” for the implicit block coupled solvers. I’m mostly looking at the matrix and trying to figure out the behaviour and the optimal settings for the linear solvers.
What would you say is your meshing specialty?
I think I know a lot about block structured meshing and I prefer it over automatic unstructured alternatives. I have created many block structured meshes in Pointwise, some of which took weeks to finish. Usually, I have a few versions of the mesh on the same geometry and I will iterate the density and distribution of the cells until getting the results we want.
Any tips for our users?
Read the user manual! Not from cover to cover, but when I have an issue with my mesh I casually scroll through the manual and it always gives me new ideas for another approach. And take some time to read about the elliptic solver settings. Mesh quality improves dramatically if you know how to set it up properly.
What project are you most proud of and why?
A rotating Formula 1 wheel. It was a complicated case that I spent a lot of time working on. The simulations just wouldn’t work with the unstructured meshes I would get from automatic mesh generators, so prof. Jasak encouraged me to make it using Pointwise. I had some trouble with resolving the patch where the wheel was in contact with the ground. It was tedious and painful but the final mesh was perfect! The case was used for validation of the coupled pressure-velocity solver. And, I won the Pointwise Wallpaper Contest with an image of that particular mesh. Now, whenever I need to make a block structured mesh, I take the whole day, play some Elvis, and it’s like meditation.
What CFD solver and postprocessor do you use most often?
foam-extend is my only choice and I use ParaView to create nice colourful pictures and Grace for graphs. FOAM requires some CFD knowledge and it’s not very user friendly. But, once you get involved in CFD and have a more complex model or a new problem, it’s the perfect answer.
Do you plan on attending any conferences or workshops this year?
I’m done for 2016. But there should be a few in 2017. The OpenFOAM Workshop is a tradition.
What do you do outside the world of CFD?
I have been dancing ballet since I was nine years old. Whenever I cannot cope with the world around me, going to the studio and doing barre makes me feel better. It’s the combination of music and movement that soothes the soul. I also like to exercise, six days a week I work out at home. I don’t want to join a gym because I mostly like to use only my body weight. Before going to bed I like to read fiction. My boyfriend got me hooked on Murakami, so I’m going through his work right now. That’s the daily routine. I also like going to the theatre and have a subscription for Croatian National Theatre’s ballet performances and occasionally some opera.
What is some of the best CFD advice you’ve ever received?
There are no dragons! It was given to me by prof. Jasak when I was trying to do CFD by reading books before trying anything by myself. He told me I need to stop being afraid of making mistakes and just do it. It helped me and I learned a lot from my own experience.
If you had to pick a place to have dinner, where would you go?
I don’t really like to go out to eat. I prefer eating at home with a good TV show in the background. I do have a sweet tooth and would recommend desserts in Kraš Choco Bar. Kraš is a Croatian confectionery manufacturer and its pralines and wafers are my favourites.