# Adaptive Fluid Simulations | Two Minute Papers #10

## Метаданные

- **Канал:** Two Minute Papers
- **YouTube:** https://www.youtube.com/watch?v=dH1s49-lrBk
- **Дата:** 21.09.2015
- **Длительность:** 2:46
- **Просмотры:** 75,351
- **Источник:** https://ekstraktznaniy.ru/video/14952

## Описание

There are computer programs that can simulate the behavior of fluids, such as water, milk, honey and many others. However, creating detailed simulations  takes a really long time, up to days even for a few seconds of video footage. Adaptive algorithms are a class of techniques that try to adapt at the problem that we have at hand. This adaptive method focuses computational resources to regions which are visible and have many fine details, and coarsens the simulation quality in regions that are not visible (or interesting). The resulting algorithm is much more efficient at simulating small scale turbulent details.

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Recommended for you - Wavelet Turbulence:
https://www.youtube.com/watch?v=5xLSbj5SsSE&list=PLujxSBD-JXgnqDD1n-V30pKtp6Q886x7e&index=7

The paper "Highly Adaptive Liquid Simulations on Tetrahedral Meshes" is available here:
http://pub.ist.ac.at/group_wojtan/projects/2013_Ando_HALSoTM/index.html
Disclaimer: I was not part of this research project, I am merel

## Транскрипт

### <Untitled Chapter 1> []

Dear Fellow Scholars, this is Two Minute Papers with Károly Zsolnai-Fehér. As we discussed before, simulating the motion of fluids and smoke with a computer program

### Source YouTube channel [0:08]

is a very expensive process. We have to compute quantities like the velocity and the pressure of a piece of fluid at every given point in space. Even though we cannot compute them everywhere, we can place a 3D grid and compute these quantities in the gridpoints, and use mathematical techniques to find out what is exactly happening between these gridpoints. Still, even if we do this, we still have to wait up to days, even for a few seconds of video footage. One possible way to alleviate this would be to write an adaptive simulation program. Adaptive means that the simulator tries to adapt to the problem at hand. Here it means that recognizes the regions where it needs to focus lot of computational

### Source: (Ando et al. 2013) [0:47]

resources on, and at the same time it also tries to find regions where it can get away with using less computation. Here you can see spheres of different sizes - in regions where there is a lot going on, you will see smaller spheres. This means that we have a finer grid in this region, therefore we know more about what is exactly happening there. In other places, you also see larger spheres, meaning that the resolution of our grid is more coarse in these regions. This we can get away with only because there is not much happening there. Essentially, we focus our resources to regions that really require it, for instance, where there are lots of small-scale details. The spheres are only used for the sake of visualization, the actual output of the simulator looks like this. It also takes into consideration which regions we're currently looking at. Here we're watching one side of the corridor, where the simulator will take this into consideration and create a highly detailed simulation - at the cost of sacrificing details on the other side of the corridor, but that's fine, because we don't see any of that. However, there may some objects the fluid needs to interact with. Here, the algorithm makes sure to increase the resolution so that particles can correctly

### Source: Ando et al. 2013 [2:00]

flow through the holes of this object. The authors have also published the source code of their technique, so anyone with a bit of programming knowledge can start playing with this amazing piece of work. The world of research is incredibly fast moving. When you are done with something, you immediately need to jump onto the next project. Two Minute Papers is a series where we slow down a bit, and celebrate these wonderful works. We are also trying to show that research is not only for experts, it is for everyone. If you like this series, please make sure to help me spread the word, and share the series to your friends, so we can all marvel at these beautiful works. Thanks for watching, and I'll see you next time!