Advection-diffusion-limited aggregation.

Much is known about diffusion-limited growth from a dilute suspension. The simplest and most famous model is diffusion-limited aggregation (DLA), in which random walkers are released one-by-one far away and become frozen where they first touch a growing fractal cluster. Real growth phenomena, such as mineral deposition in rocks, however, often involve multiple processes, such as advection-diffusion in a fluid flow, which would be difficult to simulate by random walkers. FIG. 1. (Enhanced online).