Dresden 2017 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 54: Posters - Pattern Formation, Reaction Diffusion, Chimera
DY 54.4: Poster
Donnerstag, 23. März 2017, 17:00–19:30, P1A
Numerical simulation of polygonal patterns in salt playa — •Marcel Ernst1, Jana Lasser1, and Lucas Goehring1,2 — 1Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany — 2School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK
In salt pans and playa we sometimes observe that salt crystallization due to evaporation forms polygonal salt-ridge patterns on the surface. Ridges of crystalized salt surround a flat center with a characteristic length scale of about one meter. We aim to understand the development of those polygonal structures as there is currently no comprensive theory of their formation, and different approaches to describing them range from wrinkling to cracking of the surface; none of these mechanisms reproduce the characteristic length scale of the pattern. Here we investigate a numerical model that includes the subsurface dynamics of the salt water-filled porous medium below the crust: salinity gradients drive convection cells which, in turn, interact with the development of salt ridges at the surface. The typical length scales of those convection rolls is consistent with the observed patterns. We use semi-spectral Fourier Galerkin methods to simulate the convection-diffusion-dynamics in the system and complex boundary conditions on the surface in a simplified 2d-model. We compare our results with similar experiments in Hele-Shaw cells and measurements of salt polygons in the field.