'Shear thickening' in non-shear flows: the effect of microstructure

The bizarre behaviour of a cornstarch suspension (sometimes called oobleck) is well known to all of us who have led public engagement events. At the right solids fraction, it flows smoothly at slow speeds, but can be shattered with a quick spoon movement; if you prepare a large enough sample, you can run across the surface (but if you stand still, you will sink). In rheology circles this phenomenon is known as shear thickening, though the flows described above are not necessarily shear-dominated. In recent years there has been a proliferation of research on the mechanism behind true shear thickening, using both experiments and numerical simulations of shear flows. The understanding of the underlying mechanism is improving markedly. But the paper ‘Microstructure and thickening of dense suspensions under extensional and shear flows’ (Seto, Giusteri & Martinello, J. Fluid Mech., vol. 825, 2017, R3) is the first to consider more general flows. We have, for the first time, simulations of thickening in extensional flows, which are a far better description of oobleck with a runner on top – and can begin to quantify the difference between the idealised shear thickening and the extension thickening that happens in practice

Additional file 3: Movie 3. of Development of a lecithotrophic pilidium larva illustrates convergent evolution of trochophore-like morphology

Transverse sections (from apical to vegetal) showing anatomy of the “pileus” stage of Micrura sp. “dark.” A running z-projection movie of the confocal z-series used to make Figure 5e1-e3. Specimen stained with phalloidin (white) and propidium iodide (orange). Scale bar 50 µm. (MOV 13778 kb

MOESM1 of The trochoblasts in the pilidium larva break an ancient spiralian constraint to enable continuous larval growth and maximally indirect development

Additional file 1: Fig. S1. Summary of examined labeled domains. Fluorescence ratio confocal images, maximum intensity projected, of labeled domains organized by quadrants (columns) and quartets (rows). These are the same panels shown in Figs. 2, 3, 4 and 5. Apical organ up on all panels. Labeled domains in A and D quadrants are shown from the left side, those of B and C are shown from the right side. Scale bar 50 Οm