Fluids simulation beginner

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4 comments, last by alvaromat 16 years, 1 month ago
Hi guys I have started few days ago reading articles about real time water simulation, in order to code a surf mini game. I have tried to follow Nils Thurey document about breaking waves on shallow water. http://graphics.ethz.ch/~thuereyn/download/nthuerey_070503_realtimeswswaves.pdf I have also read the fluid basic notes from Muller and Bridson at GD2007 at someone suggested at the Conjugant Gradient Method post. I have read other articles like Stam ones with FFT and the Layton and M.van der Panne one explaining a numerically efficient algorithm for water waves. I can understand without much problem most of the theoric stuff, but i get lost when any of the autors start resolving any of differential equation into a linear form (I would like to be able to simulate the algorithm on paper) I am wondering if u guys know any book/webpage/resources with examples that could help me with this part of the fluids simulation. Because they start talking about semiLangrangian, explicit, implicit methods, resolving differential equations and i just stared on front of it, but i am not able to repeat the process by myself without having the articles in front of me. Thank guys
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Stam has his paper Fluid Dynamics for Games, and Harris has an article in GPU Gems that has source code on the CD-ROM (I believe this is downloadable from nvidia's site).
I don't think the Stam approach is going to be useful without significant changes because it's designed for internal fluid motion - not for motion of fluid(s) with fluid boundaries.

Are you sure you actually want physical simulation of the water (i.e. make it fully interactive) - or is it sufficient to calculate the water surface, and then use physics (presumably) for the motion of your surfer on top of it? Full simulation will likely be slower, less reproducible (so harder to get good gameplay with), harder to implement, and maybe not even look as good.
There is a paper book that I highly recommend for anyone who wants to learn how the theory of fluid flow is turned into numerical problems. If your background isn't fluids, this book may also open up your eyes about the nature of fluids also, even if you already found it intuitive:

Computational Fluid Dynamics - John D. Anderson

So, its really expensive from Amazon. But....you should be able to find it for MUCH cheaper from Bookfinder. There are some super expensive copies there, but there were several around US$50 or less.

This is a fantastic book if you care to learn the way numerical discretization of PDE's, in particular for fluids, is formulated, and why. It does directly address the original issue of representing these things in a linear form, in a very intuitive manner.

There is also another book, similarly good though more advanced:

Computational Fluid Mechanics and Heat Transfer - Tannehill, Anderson, and Fletcher. (Its a different Anderson.)

Interestingly, though the second book is nearly 3 times as thick, it is cheaper than the first (the Amazon price anyway).

[Edited by - grhodes_at_work on March 5, 2008 3:59:59 PM]
Graham Rhodes Moderator, Math & Physics forum @ gamedev.net
Quote:Original post by MrRowl
I don't think the Stam approach is going to be useful without significant changes because it's designed for internal fluid motion - not for motion of fluid(s) with fluid boundaries.

Are you sure you actually want physical simulation of the water (i.e. make it fully interactive) - or is it sufficient to calculate the water surface, and then use physics (presumably) for the motion of your surfer on top of it? Full simulation will likely be slower, less reproducible (so harder to get good gameplay with), harder to implement, and maybe not even look as good.


The OP was concerned less with free surfaces than with the million other common topics.
Hi guys first of all thanks a lot for the papers, i will go over them later.

Taby

I have read Harris article for the GPU, but my point is to be able to solve the equations by myself. Although Stam video game article is quite cool and after sitting on it for a while I have decided to not copy an paste :D

McRowl

I would like to code Thurey implementation, as a first step on proper fluid simulation, but u are probably right since the animation of Thurey gives a maximun of 54 fps, so probably i would end up coding either a surface wave simulation or a modified "heightfield fluid hello world". But i still want to learn fluid simulation to start doing more complicated things

grhodes_at_work

Thanks dude, i saw that book on amazon but only had 1 review so i wasnt too sure on buying it, but if u recommend i will get it

Thanks guys



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