Ghostbusters Ecto-1 is haunted by Aerodynamic Drag

[@seanriopel3132]

I am absolutely awestruck by your videos. I can literally watch them for hours on end.

[@aks47u]

explains a lot

[@absalomdraconis]

You should probably do a few more cars. A 1930's era car, something boxy from the 80s/90s, and something modern should provide some interesting contrasts. Though admittedly, the weirder the car, the more the fun.

[@jorcyd]

Flex-Tape guy : "Now that's a lot of drag !"

[@RafaGmod]

must be cool to see the uncompressed video, youtube kills it hahahahha

[@ProjectPhysX]

It's over 4GB for 3 minutes uncompressed 1080p :D

[@MrBlueSky1293]

Now do Aerodynamics of a single Original Recipe Kentucky Fried Chicken Leg, complete with all 11 herbs and spices.

[@NoobCastProductions]

KZbin's compression algorithm is dying from your videos.

[@ThalassicOddity]

Incredible!! It'd be cool if I could use this to simulate some fluid dynamics like a whale splashing on to water or something for example.

[@hossein.najafi]

Wonderful massive simulations! Dr. Lehmann can you also please make a hull performance simulation? a simulation to calculate open water hull resistance and also seakeeping. I tried to make something with your Github code but still am trying to figure out the structure and the procedures :). Thanks for giving so much back to community generously :)

[@yytffs]

Man how do I even learn this super-cool stuff? I was into game dev, low-level but cannot find resources for physics related stuff for beginners like me.

[@ProjectPhysX]

Once upon a time I was a beginner too! Here is some links to learning material: - LBM intro video: kzbin.info/www/bejne/qqPZhHV9rrBqask - LBM model/equations: doi.org/10.15495/EPub_UBT_00005400 LBM software: github.com/ProjectPhysX/FluidX3D/blob/master/DOCUMENTATION.md

[@JuliusBurton]

It would be really cool to see a simulation with a bird flapping its wings. If you can find a good bird animation somewhere.

[@Thee_Sinner]

When these simulations begin, like is shown at 1:00, so they start with an instantaneous velocity? Or does it ramp up? I don’t have the education to back this up or really even know how to explain myself properly, but I suspect it is the former. It looks like there are waves or ripples in the simulated flow that might be caused by a sudden start.

[@ProjectPhysX]

Yes this one starts with instantaneous velocity.

[@Thee_Sinner]

@@ProjectPhysX I’d be interested to see how much a ramp up (or a 0-60 like another commenter suggested) would change what the flow looks like. Is this something you’ve compared before?

[@TheUnderscore_]

At a much simpler level, would it be possible to simulate the sound coming from the vibration of a material (i.e. a metal pipe or violin string) using FluidX3D? I don't know much about this whatsoever, so I apologize if this is something you've stated to be able to (not) do.

[@ProjectPhysX]

Not sure. LBM generally can do aeroacoustics. The sound source can be turbulent vortices or some oscillatory boundaries. But in the latter case I think a simpler wave-based model would be better suited.

[@TheUnderscore_]

@@ProjectPhysX Thanks so much! I thought maybe physical modeling synthesis might be the best route (especially considering efficiency), but it'd be cool to do otherwise. Have a great day!

[@ektorthebigbro]

Day one of asking for a sound simulation

[@carrapaz3645]

What is the drag coefficient of the car? 😮

[@petterlarsson7257]

Yes

[@Eclipsar32]

Just wondering what would be the aerodynamics of a kids playground. Always love to see your simulations

[@tedyplay4745]

Can you please make a video tutorial?

[@dar1e08]

Hi Dr Lehmann, what is the long term application for this code? At the moment the license prohibits commercial use so how would this code benefit those of us working in industry?

[@ProjectPhysX]

I have several long-term plans for this software: My main goal is to make CFD simulations accessible to everyone. Free of charge, no limitations on hardware, super fast, compatible with any hardware and operating system. Many researchers, me included back in my PhD time, don't have the money and time for very expensive yet dog-slow commercial software. Writing my own was the only way to get my PhD studies done on the limited hardware my university could afford without losing years in simulation runtime. After my PhD I figured FluidX3D would be beneficial to many other researchers as well, especially since it reduces hardware cost by about 100x due to the lower memory footprint, and electricity cost by about 2000x due to the much higher efficiency. It finally allows detailed simulations on cheap off-the-shelf gaming hardware. And when you see commercial CFD being offered as a service with hourly billing, you know they have no motivation to make it any faster. I have no regrets to make them try harder or lose customers to a better and free alternative if they don't. So for now I published the source code with a no-cost non-commercial source-available license. I made FluidX3D free of charge to everyone, only excluding commercial and military use. I don't want others to use my work as a money printer, or to misuse it for military applications. For the future I'm planning to open up the tool for commercial use too, in exchange for a license fee. Companies who make huge revenue with such software can also pay for it. For non-commercial use it will always remain free and unlimited. I have to get a few construction sites done along the way though; most notably some technicalities in the code for specific applications, finish writing the commercial license and some bureaucracy. It's not like I have the need to earn money with the software though and turn it into a business. FluidX3D is a fun hobby project for me. I love programming and making computers do useful things. Working on this software teaches me a lot.

[@dar1e08]

@@ProjectPhysX Hi Dr Lehmann, thank you for taking the time to write such a comprehensive response. I think what you are suggesting is completely reasonable. What I would suggest (as someone who is currently going through this) is that not all commercial companies are in the same position. There are older established companies with large budgets and workloads but there are also have companies and people who are just starting out with uncertain workloads and limited cash. The problem is that a lot of the software houses are not interested in the people just starting out, their license terms are typically 12 months minimum with pricing structures that get cheaper per core meaning that it is almost impossible to be competitive as a small outfit. To be honest this has lead to a lot of complacency at the larger companies. If you could find a way to keep a flat pricing structure & a way to be flexible on the licencing that would go a long way to helping to level the playing field.

[@hossein.najafi]

Brilliant vision Dr. Lehmann

[@placeholder1967]

hmm i wonder how bad the gas mileage is

[@someguy999]

Someone made a replica, which got 8mpg!

[@Rau379]

Hi Lehmann, nice work! I have started my studies in CFD a year ago. So, I have written a code to solve the problem of Lid Driven Cavity. The reynolds number was laminar, so It wasn't complex. What do you suggest for the nexts steps about my study?

[@karan17S9]

@ProjectPhysX Can you also do MonteCarlo simulations also?

[@immortaldev1489]

is there a way to get drag/lift from this simulation, I haven't been able to find a way yet

[@ProjectPhysX]

Yes: github.com/ProjectPhysX/FluidX3D/blob/master/DOCUMENTATION.md#liftdrag-forces

[@firebeardlongfellow5295]

THE GOO IS HERE!!!!!!!

[@a_witcher94]

would it be possible to have a sim run from 0-60km/h for one of those videos? i would love to see that instead of the model hitting a 60km/h wall of air ^^

[@A330plaen]

Do an aerodynamics of a person being thrown head-on at mach 15 speed

[@Nickzzzera_]

Is this plotting vorticity magnitude?

[@ProjectPhysX]

Yes, Q-criterion isosurfaces colored by velocity magnitude.

[@rassenasse8196]

Can you do the xb-70 valkyrie i want to see it riding the pressure wave

[@ProjectPhysX]

I won't do military aircraft

[@ummerfarooq5355]

I wait for the day when we no longer use anything less than fp64

[@akshayvibhute97]

How cute! CFD without validation - because who needs Computational Fluid Dynamics when you can have Colorful Fantasy Drawings? While the effort which you’ve put as a Software Developer is commendable, unfortunately for you, the Industry requires accurate results and not fancy animations. Therefore I request you to incorporate missing stuff in your code instead of boasting about how fast your solver is, when other ‘commercial’ solvers are managing better accuracy despite having coarser mesh and lower computational times.

[@ProjectPhysX]

Haha more color more better. I did this simulation over 2 months ago, and since then I'm writing on validation cases and the one missing piece for external aerodynamics applications which is a better boundary model. And you don't request me anything lol.

[@seanriopel3132]

​@@ProjectPhysXdon't you just love arrogant know-it-all's

[@kerrermanisNL]

Weird way to request features

[@MrZwulch]

I request you to do it instead of complaining in the comment section

[@jorbedo]

Sounds like a competitor craving to have a 5% of your brain capacity Dr. Lehman, such a arrogant a55hole... his only goal is for you to get mad and leave the development, your community supports you, don't waste your time on people like that.