Pattern formation in the geosciences
An experimental research group is being established to study the dynamics that occur during the solidification of complex fluids, such as colloidal dispersions, or wet soils.
As group leader, my interests lie in pattern formation in geophysical and environmental settings; in the propagation and organization of fractures; and in the dynamics of colloidal dispersions. In many cases this work is inspired by naturally observable features such as patterned ground, limestone growths in caves, columnar joints, or vegetative patterns.
Applications for group members are being solicited, at all levels. If you are interested in joining this group, please contact me by email at lucas.goehring at ds.mpg.de with a CV and statement of interests.
The group has three initial research directions:
Freeze-thaw instabilities in soils
In cold environments, on Earth and Mars, thermal variations drive a range of processes, which can lead to the large-scale patterning of landscapes into arrays of stripes, circles, or polygonal networks.Broadly, these patterns arise from both instabilities in the freeze-thaw of wet soils, and from fracture due to thermal stresses. We aim to understand the origins, scaling, and dynamics of these patterns though analogue experimentation, theory, and, potentially, field work.
Organization of crack patterns
A growing crack releases energy by modifying the stress in its vicinity. Interactions between cracks, or between a crack and its environment, can be complex, but often result in simple structures such as spirals, waves, or other patterns. We seek to understand the fundamental question of crack path prediction, and its application to cases such as nano-fabrication techniques, detection of subsurface features through crack patterns, or analysis of the craqulere of paintings. Even the growth of veins in leaves may follow similar rules.
Dynamics of drying colloidal dispersions
Colloidal dispersions, be they common paint or clay, or the ingredients of photonic crystals and artificial opals, evolve by a complex set of physical mechanisms, when they dry. A suspension of particles in fluid may gel, crystallize, crack, buckle, segregate (if there is more than one type of particle), or otherwise deform in response to forces arising in the disparate phases of the mixture. We are engaged in exploring, and explaining, the rich array of patterns evident in a drop of drying paint.