We take fluid dynamics for granted. Pour some milk in a glass, let some honey ooze out of a bear’s head into your tea, and it happens according the laws of physics—perfectly—every single time. But even though we may have a familiarity with and an intuition for what happens when a dollop of cream is dropped or a bottle of champagne is popped, the physics of those interactions is still super complex, and thusly very difficult to simulate with computer models. But simulations are doubtlessly getting better and better, and already giving reality a run for its money, as evidenced in part by the above video.

The video comes from Károly Zsolnai-Fehér and his YouTube channel, Two Minute Physics, and is actually a commentary on a paper authored by four students at the University of Freiburg entitled “An Implicit Viscosity Formulation for SPH Fluids.”

In the clip, Zsolnai-Fehér discusses one particular aspect of simulating fluid dynamics: viscosity. He notes that viscosity is defined as a fluid’s resistance to deformation, and then discusses—and shows—how the research done in the paper has helped to better simulate the viscosity of fluids.

Zsolnai-Fehér points out that having a solid grasp on simulating viscosity means more realistic fluid dynamics for multiple reasons, including, but not limited to:

• Improving other simulations, like melting, as the melting of many objects essentially translates into a change in viscosity over time.
• Improving simulations of “two-way coupling,” or the effect that an object has on a fluid, and the simultaneous effect that that fluid has on that same object.
• Placing multiple fluids with varying densities and viscosities into the same interactive area, and having them interact in a realistic manner

Simulation of multiple fluids with varying viscosities and densities interacting with each other.

Zsolnai-Fehér goes on to say that these “robust techniques that work for small- and large-scale simulations with multiple objects and material settings that can possibly change in time” are exactly what visual effects artists want, and need, to create more believable simulations of real fluid dynamics. Which means that 2018 Aquaman movie is probably going to be insanely realistic. Except for there being a superhero that can talk to fish and all that…

What do you think about this simulation of viscosity? And what are some of the best fluid dynamic simulations you’ve seen in films or video games? Let us know in the comments section below!

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Images: Two Minute Papers