On the left, there is a videogame snapshot. It is generated through a visual effect software, used for films, video games, and animations. You can see the air pushing the balloon and it looks pretty realistic. But, in reality, this is the picture on the right is the one that represents almost exactly how air flows around the balloon at this particular circumstance.
It is generated by numerical simulation software.
What you see on the picture of the right, is actually the visual aid for a lot of numbers working on a computer to try to solve one of the hardest equations ever discovered, the one that describes turbulent fluid flow. This is a Computational Fluid Dynamic simulation.
The goal of a CFD simulation is to predict on a computer the behavior of flow, like water or air, as it would happen in the real world. Behind the scenes of a CFD image, there’s a lot of mathematics, physics and computer science going on.