Explore the Possibilities

10 secrets to a stunningly fun CFD simulation

By Simon Fischer

Another Friday afternoon, another chance for a fun CFD simulation! Those tiny little projects we do out of pure curiosity. The ones we sometimes do just because we can. The ones we do because we all like those five minutes of fame when our engineering mates give us their kudos. But most importantly, the ones we do because we love fluid mechanics.

We all know it’s true.

But, all that motivation aside, what sets the brilliant, outstanding, engaging fun CFD simulation apart from the vast majority of attempts. What is the secret of those masterpieces of fun CFD simulations that inspire the masses?

The honest answer is “I have no idea”. But I have some educated guesses.

Here are my top-ten tips to make your fun CFD simulation project inspire the masses

1. Do it for the sake of itself

Whatever you choose to simulate, in first place do it because you want to do it. Because you really want to see that thing running and get some engineering insights.

One fun CFD simulation project I did just because I always wanted to is E.C. Escher’s waterfall. Funnily it quite nicely represents the concept of doing something just for the sake of itself.

Do fun CFD simulation projects for the sake of themselves.

2. Do something creative

After Elon Musk lifted the secret, how many times have you seen the aerodynamics simulation of the Tesla cybertruck? Frankly, after the fifth one done quick and dirty in two days, I was so bored by it that I could barely stand it.

CFD can be used for so many things. With the right tool CFD is capable of far more than single phase flow of a car (no doubt even the latter can have a great appeal, see #6). When you want to do something that catches peoples' interest, be creative in your choices. Take this great example by my former colleague Nipun:

Cheers! Applied fluid dynamics simulation. Don’t drink too fast!

3. Take care of the details

As simulation engineers it has taken us decades to build up credibility of CFD in serious engineering processes. Thousands of CFD engineers before you have spend millions of hours to achieve the standing CFD today has. However meanwhile, thanks to commercial tools, with all their automation, ease-of-use, stability, performance and postprocessing capabilities, CFD simulation has become accessible to many. Gone are the times when only the hardcore numericists could handle the codes.

That brings us to a serious word of caution for any fun CFD simulation: even if it’s just for fun, even if the programs are easily to handle, the devil is ALWAYS in the details. And only if you are willing to take care of the details, will you make a high quality CFD simulation. Mesh matters, boundary conditions matter, model choices matter! A high quality CFD simulation requires research. Guaranteed, your fellow engineers will distinguish the quality ones from the quick and dirty ones.

Don't destroy the credibility of CFD, now no longer being flagged colorful fluid dynamics or color for directors! It’s your responsibility with each and every CFD simulation, and fun CFD simulations are no different.

4. Be prepared to invest more than you thought

If you take #3 seriously, I can tell you you will always run into #4. The nature of #2 implies that you will probably explore something, you have not done before, that implies you will run into traps you did not see coming, you need to find solutions to problems you did not expect, you will understand the problem requires way more complex physics and a way finer mesh and time step than you would have ever thought.

In short, you will engineer innovation.

5. Raise curiosity and then deliver insight

This is the key of every well-told story. And well made fun CFD simulations are nothing but a story told in the format of computer aided engineering. At the core of storytelling is the idea of bonding the audience to the story, create suspense to keep the bonding, raise the question “How is this going to turn out?” and then at the moment of maximum tension, at the ultimate crisis choice of the hero, deliver an insight the audience has not had before.

6. Make the simulation relatable to the masses

Engineers are one bunch, “common people” are a huge audience. If you really want to help with the democratization of CFD the latter should be your target just like the former. If you are able to make that stretch with your simulation, success of your fun CFD simulation project will follow. Now I understand this is not an easy one, serving the longtime CFD engineer, who is into turbulence model details and the dude from next door at the same time is pretty tricky. But after all we are all human!

7. Make postprocessing a visual firework

I love that one. Because it is always an invitation to the old school CFD folks to jump onto the good old “color for directors/colorful fluid dynamics” train!

Here’s my response to them all the time, inspired by one of my personal legends of science, Richard Feynman:

Feynman: “I have a friend who’s an artist [..]. He’ll hold up a flower and say ‘I as an artist can see how beautiful this is but you as a scientist take this all apart and it becomes a dull thing,’ Feynman: ‘I can appreciate the beauty of a flower. At the same time [..] I could imagine the cells in there, the complicated actions inside, which also have a beauty. [..] there’s also beauty at smaller dimensions [..] The fact that the colors in the flower evolved in order to attract insects to pollinate […] adds a question: does this aesthetic sense also exist in the lower forms? Why is it aesthetic?

All kinds of interesting questions which the science knowledge only adds to the excitement, the mystery and the awe of a flower. It only adds. I don’t understand how it subtracts. ”

8. Make sure your fun CFD simulation is relevant

Christmas, soccer world championships, Halloween, St. Patricks day, Superbowl,… it’s the 101 of marketers to have those on the schedule and then, right on spot, have some fun CFD simulation go out the door (see my project for the 50th Apollo 11 anniversary).

If done right and delivered on time, #8 will be a massive – if not the – booster to make your fun CFD simulation travel the world: two great examples stem from my colleague Prashanth who participated in the FIFA World Cup AND the Superbowl. The simulations were done with care, insightful, relevant to a huge audience and… delivered spot on. Results on social media followed.

More than just fun: CFD delivers insight into CR7’s legendary free-kick


9. Take your fun CFD simulation project seriously

They are called fun CFD simulation projects, but the secret to make something that matters to the world is, tackle it as seriously from a technical perspective as any real engineering challenge! Follow tips 1 to 10 with care and chances are high you will succeed.

Why so serious? When CFD simulation can be so much fun.

10. Choose a fun-to-work-with tool

And even though #9 sounds like hard work (because it is), my #10 is the ultimate key to success: A fun CFD simulation project has to be conducted with joy. And while we probably all love doing CFD, there is one thing that will further raise the joy – and that’s using the right toolset:

Further reading

Read Simon's full blog here