134
(a)
(d)
(g)
4. SIMULATING GROWTH AND FORM
(b)
(e)
(h)
(c)
(f)
(i)
Fig. 4.39a-i. Objects resulting from the accretive growth model in which the deposition process is exclusivelydriven by the local
nutrient gradients k(c) in (4.25),for various Pe numbers
Fig. 4.40. Section through the simulation box made in the xz-plane, showing
the nutrient concentration around the
growth forms. Black indicates a high
concentration, white visualizes a depletion of nutrients, and the section through
the object is shown by using white colored lattice sites. In the left picture the
nutrient distribution is shown for the
diffusion-limited case (Pe :::: 0) and in the
right picture the flow-dominated case is
depicted (Pe :::: 3.0);in both cases the flow
was directed from the bottom to the top.
The objects were generated with the accretive growth model using only k(c) in
(4.25).
through the three-dimensional lattice at the xy-plane are made, showing the
concentration of nutrients at the object, for both phases, for the extreme
values of the Peclet numbers. Black indicates a high nutrient concentration,
while depleted areas are colored white. Fig. 4.41 shows the morphologies of
objects generated in the simulations where the deposition process is driven