Gray-Scott Model at F 0.0260, k 0.0530  

These images and movie demonstrate the behavior of the Gray-Scott reaction-diffusion system with σ=Du/Dv=2 and parameters F=0.0260, k=0.0530.

Initial chaos soon (after roughly 1500 tu) produces small negative rings and solitons; the latter prevail and establish an ordered hexagonal packing throughout the field by about 20,000 tu. Synchronized oscillation continues indefinitely. Pattern continues to rearrange itself for at least 250,000 tu.    (glossary of terms)

             increase F









      
decrease k
      
after 120 tu
after 600 tu

15 frames/sec.; each fr. is 40 iter. steps = 20 tu; 1800 fr. total (36,000 tu)









      
increase k
      
after 2,200 tu after 9,000 tu after 36,000 tu
             decrease F
(Click on any image to magnify)

In these images:

Wavefronts and other moving objects have decreasing u values (brighter color) on the leading edge of the blue part of the moving object, and increasing u (light pastel color) on the trailing edge. This is true even for very slow-moving objects — thus, you can tell from the coloring what direction things are moving in.

''tu'' is the dimensionless unit of time, and ''lu'' the dimensionless unit of length, implicit in the equations that define the reaction-diffusion model. The grids for these simulations use Δx=1/143 lu and Δt=1/2 tu; the system is 3.2 lu wide. The simulation meets itself at the edges (periodic boundary condition); all images tile seamlessly if used as wallpaper.

Go back to Gray-Scott pattern index


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