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In this article we use a lattice-Boltzmann simulation to examine the effects of shear flow on an equilibrium droplet in a phase separated binary mixture. We find that large drops break up as the shear is increased but small drops dissolve. We also show how the tip-streaming, observed for deformed drops, leads to a state of dynamic equilibrium.

We report the application of the Monte Carlo simulation to phase separation dynamics. First, we deal with the phase separation under shear flow. The thermal effect on the phase separation is discussed, and the anisotropic growth exponents in the late stage are estimated. Next, we study the effect of surfactants on the three-component solvents. We obtain the mixture of macrophase separation and microphase separation, and investigate the dynamics of both phase separations.

The local mobility of particles in highly supercooled liquids is demonstrated to be spatially heterogeneous on time scales comparable to the structural relaxation time τ_α. The particle motions in the active regions dominantly contribute to the mean square displacement, giving rise to a diffusion constant systematically larger than the Stokes–Einstein value. The diffusion process eventually becomes homogeneous on time scales longer than the life time of the heterogeneity structure (~ 3τ_α). The heterogeneity structure in the local mobility is very analogous to the critical fluctuation in Ising spin systems with their structure factor being excellently fitted to the Ornstein–Zernike form.

For rigid chiral objects in the low Reynolds number of shear flows, both experimental and theoretical results show that the chiral objects and their enantiomers will migrate in the positive or negative vorticity directions. This phenomenon is widely explored for the possibility of separation of chiral objects in shear flow. Within the simplest twisted "H" molecule model of hydrodynamic interactions of particles, we have calculated the hydrodynamic forces exerted on chiral twisted "H" molecules by shear flows. The chiral parameters that determine their different migration forces in shear flows are identified. The analysis may also be extended to study other complex motions of chiral objects in natural situations and microfluidic cells as well as important chiral-flow interactions, such as the interparticle interactions mediated by fluid flows.

Chiral objects in a shear flow experience a chirality-specific lift force. Shear flows past helices in low Reynolds number regime are studied by a highly efficient iterative method, based on the analytical solution of a sphere in uniform flow. The chirality-specific lift forces in the vorticity direction experienced by helices are dominated by a set of helix geometry parameters: helix radius ($\rho$), pitch length (b), number of turns and helix phase angle. Its analytical formula is firstly given. The chirality-specific forces are the physical reasons for the chiral separation of helices in shear flow. Our results are qualitatively in agreement with the simulation results and well supported by the latest experimental observations.

We consider the chiral properties for a helix in uniform shear flow. We decompose the helical structure into arrays of $N$ closely packed beads with radius $a$. In low Reynolds number regime, the chirality-specific lift forces in the vorticity direction experienced by helices are given by a set of helix geometry parameters: helix radius $(\rho )$, pitch length $(b)$, number of turns $(n)$ and helix phase angle $(\varphi )$. The analytical formula of the force is firstly given. The chirality-specific forces are the physical reasons for the chiral separation of helices in shear flow. Our results provide new insights into the separations of all kinds of chiral objects.

Hemolysis in blood-contacting devices severely affects the health of users, and computation fluid dynamics (CFD) simulation is a crucial method for hemolysis analysis. Medical equipment has high requirements for simulation accuracy. Modification of the turbulence model is one of the most effective ways to improve efficiency. In this study, we designed nozzle models to simulate hemolytic shear flow, varying the degree of shear flow through different nozzle orifice sizes. The study acquires microscopic flow results through Particle Image Velocimetry (PIV) experiments, and the Sparlart–Allmaras (S–A) model was modified based on the experimental results. In the study, we obtained the influence characteristics of the model coefficients on the simulation results and completed the accuracy correction. The results showed that the model coefficient $c_{b1}$ has the most significant effect on the simulation results. Correcting $c_{b1}$ to about 200% of the standard value can significantly improve the simulation accuracy, and the high shear flow intensity corresponds to a slightly lower correction value. The model modification eliminates the simulation error in the high-speed area, and the comparison results show that it is superior to the standard turbulence model.

The initiation and steady-state dynamics of granular shear flow are investigated experimentally in a Couette geometry with independently moveable outer and inner cylinders. The motion of particles on the top surface is analyzed using fast imaging. During steady state rotation of both cylinders at different rates, a shear band develops close to the inner cylinder for all combinations of speeds of each cylinder we investigated. Experiments on flow initiation were carried out with one of the cylinders fixed. When the inner cylinder is stopped and restarted after a lag time of seconds to minutes in the same direction, a shear band develops immediately. When the inner cylinder is restarted in the opposite direction, shear initially spans the whole material, i.e. particles far from the shear surface are moving significantly more than in steady state.

This study theoretically investigates receptor–ligand-mediated endocytosis of nanoparticles (NPs) in wall shear flow. The endocytosis is modeled as a birth–death process and relationships between coefficients in the model and the wall shear rate have been derived to deal with the effects of the shear flow. Model predictions show that flow-induced alteration in bond formation rates does not affect the endocytosis significantly, and the suppression of hydrodynamic load on endocytosis is eminent only when diameters of NPs are large (around 700nm) and the shear rate is sufficiently high. In the latter case, it is shown that the hydrodynamic load suppresses the initial attachment of NPs to cells more than the following internalization. The model also predicts that shear-promoted expression of certain ligands can lead to observable increase in the number of endocytozed NPs in typical flow-chamber experiments, and the promotion can also cause selective endocytosis of NPs by cells at high shear rate regions if the ligand surface density on NPs or the original expression of receptors on cells in the absence of flow is low.

Laser ektacytometry is a technique widely used for measuring the deformability of red blood cells (erythrocytes) in blood samples in vitro. In ektacytometer, a flow of highly diluted suspension of erythrocytes in variable shear stress conditions is illuminated with a laser beam to obtain a diffraction pattern. The diffraction pattern provides information about the shapes (shear-induced elongations) of the cells under investigation. This paper is dedicated to developing the technique of laser ektacytometry so that it would enable one to measure the distribution of the erythrocytes in deformability. We discuss the problem of calibration of laser ektacytometer and test a novel data processing algorithm allowing to determine the parameters of the distribution of erythrocytes deformability. Experimentally, we examined 12 specimens of blood of rats under the action of 4 shear stresses. Analysis of the data shows that in conditions of a limited range of digitizing the diffraction patterns, the measurement errors for the mean deformability, deformability scatter and the skewness of erythrocytes distribution in deformability by our method are respectively 15%, 20% and 20%.

The initiation and steady-state dynamics of granular shear flow are investigated experimentally in a Couette geometry with independently moveable outer and inner cylinders. The motion of particles on the top surface is analyzed using fast imaging. During steady state rotation of both cylinders at different rates, a shear band develops close to the inner cylinder for all combinations of speeds of each cylinder we investigated. Experiments on flow initiation were carried out with one of the cylinders fixed. When the inner cylinder is stopped and restarted after a lag time of seconds to minutes in the same direction, a shear band develops immediately. When the inner cylinder is restarted in the opposite direction, shear initially spans the whole material, i.e. particles far from the shear surface are moving significantly more than in steady state.