MULTI-BOUNDARY RESULTS
Two boundaries - Exaggerated tension difference
Downloadable .avi file (8.32 MB)
In this first simulation, a second grain boundary was added to the combined migration and diffusion problem. There is an unrealistically large difference in the surface tension on the bottom interface to exaggerate and more easily highlight the effects of this double grain boundary system. Once the grain and groove angles have formed, both boundaries begin to flow to the right. The ridge formed by the left grain boundary causes the groove formed by the right grain boundary to move upward. This causes the ridge formed by the right grain boundary to flow even higher, producing this large difference in the two boundaries.
Five boundaries - Even spacing
Downloadable .avi file (7.76 MB)
This simulation shows the migration and diffusion effects of five grain boundaries evenly spaced apart. The surface tension has been reverted back to more realistic numbers for this study. As the system evolves, the boundaries flow at the same velocity, but the ridges and grooves formed behave differently from one another. Since the leftmost groove is free on the left side, it is able to form deeper than the other grooves. In general, the groove depths and ridge heights seem to ascend to the right, but there is one interesting exception to this observation. The ridge formed by the second to last boundary is actually lower than the one formed to the left of it. This seems to happen because the rightmost ridge is free to rise higher than the other, causing the rightmost groove to rise with it. This higher groove interferes with the second to last ridge, causing it to form lower than the one to the left of it.
Five boundaries - One isolated (4-1)
Downloadable .avi file (8.17 MB)
This simulation shows five grain boundaries again, but the last one is isolated to the right. The group of four evenly spaced boundaries behaves similarly to the five evenly spaced boundaries shown before. The fifth, isolated boundary was far away enough so that its effect on the second to last boundary was minimal. The interesting note here is that the large ridges formed by the two rightmost boundaries cause the last groove to evolve very deeply compared to the other grooves.
Five boundaries - Left and right isolated (1-3-1)
Downloadable .avi file (8.16 MB)
This is another five grain boundary experiment, but now both the leftmost and rightmost boundaries are isolated. Without looking at the leftmost boundary, the system behaves like the 4-1 configuration above. Since the leftmost boundary is isolated enough to not be constrained significantly by the other boundaries, it forms a large ridge and the next groove is able to evolve to a lower depth. This characteristic is similar to boundary isolated on the right.