Figure 5.

Tree-like patterns. Pictorial representation of increase in node distance (r _n) with increasing θ for (a) second generation structure where ${\delta }_1=200\mu m,$ and δ ₂ = 400 μm (b) third generation structure with ${\delta }_1\mathrm{=200}\mu m$, ${\delta }_2=300\mu m,$ and ${\delta }_3=400\mu m$. (c) Images show a controlled non-uniform interaction of fingers initiating over the entire interface. Image-i show only the controlled first generation structures i.e, branches emerging out of the shaded circular portion (reference circle) divide only once before they merge with the circumferential ring. Image-ii shows second and image-iii shows third generation structures over 360° interface. All the fingers in image-iii are made to under go controlled interaction for their entire lengths thus producing a cayley-tree structure in its actual/ideal form. Parameters set for shaping these structures are, b ₀ = 50 μm, R = 15 mm θ = 7.5° and V = 4 μm/s.