How do we model fluids that behave partly like solids?

A physics-based Maxwell model with variable parameters improves the description of viscoelastic flows where material properties change during deformation.

🔗 https://pubs.aip.org/aip/pof/article/38/2/022012/3380412/Physics-based-Maxwell-model-with-variable

#Viscoelasticity #FluidDynamics #Rheology #PhysicsOfFluids #Modeling

Interested in understanding how properties of rocks at the lattice-scale influence properties at much larger length scales? Check out the new iSTRUM blog post from Diede Hein on how dislocations in mineral grains influence the dissipation of energy of a seismic wave: https://istrum.github.io/blog/dislocations-transient-creep/

#geology #geophysics #rheology #science #rocks

Watch Hagfish Slime Unfurl

The eel-like hagfish has one of the best defenses in the ocean. When threatened, it releases a slime that clogs the gills of its predator but allows the hagfish itself to slough off the slime and escape. The hagfish slime’s secret weapon is long protein threads, which are initially rolled into bundles called skeins. Seen above, these skeins resemble the yarn skeins knitters and crocheters buy, but a hagfish’s skeins are only as big as the width of a human hair.

When water flows by quickly enough, the thread in a skein begins to unwind and stretch out. With enough threads unwound, the slime gets stretchy and viscous. Researchers found that it takes relatively little flow to begin this unwinding because the adhesion between threads and the surrounding fluid is higher than the thread-to-thread sticking power. (Research and image credit: M. Hossain et al., video)

#biology #fluidDynamics #hagfish #physics #rheology #science #viscoelasticity

Predicting Yield

We’ve all experienced the frustration of ketchup refusing to leave the bottle or toothpaste that shoots out suddenly. These materials are yield stress fluids, which transition from solid-like behavior to liquid flow once the right amount of force is applied. A new study suggests that — despite their wide range of characteristics — these fluids share a universal relation: their yield transition (when they start to flow) depends on their characteristics when at rest. Interestingly, this relationship seems to hold not only for polymeric fluids like the one in the study but also nonpolymeric ones. (Image credit: haideyy; research credit: D. Keane et al.; via APS Physics)

#fluidDynamics #physics #rheology #science #yieldStressFluid

Interesting : In a #fibrin #gel, inseritng 5% inclusions lead to a 10× increase of #shearModulus and switch from softening to stiffening behaviour. #Collagen gels also show some of these features.

#biomechanics #rheology

@Rxiv_mechanobio
cc @JonFouchard