More fun with Lattice Boltzman Method (LBM) fluid simulations

Back in September 2010 I was experimenting with Lattice Boltzmann Method (LBM) fluid flows.

At that time I managed to translate some (probably Fortran) LBM source code provided by the now defunct “LB Method” website (here is how LB Method looked around that time). The algorithms worked and did give me some nice results, but there were problems like lack of detail and pulsating colors due to my display routines scaling minimum and maximum velocities to a color palette.

Yesterday I was looking around for some new LBM source code and found Daniel Schroeder‘s LBM page here. Daniel graciously shares the source code for his applet so I was able to convert his main LBM algorithms into something I could use in Visions of Chaos. Many thanks Dan!

Using Dan’s code/algorithms was much faster than my older code. It also allows me to render much more finer detailed fluids without causing the system to blow out. I can push the simulation parameters further. Dan’s method of coloring solved the pulsing colors issue my older code had and includes a really nice way of visualizing the “curl” of the flowing fluid. Tracer particles are also used to follow the velocity of the underlying fluid to give another way of visualizing the fluid flow. Once particles leave the right side of the screen they are buffered up until they fill up and can be reinjected to the left side of the flow. Tracer particles help seeing the vortices easier than shading alone.

With less memory requirements (another plus from Dan’s code) I was able to render some nice 4K resolution LBM flows. This movie must be watched at 4K if possible as the compression of lower resolutions cannot handle displaying the tracer particles.

The new LBM code is now included with Visions of Chaos.

Jason.

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