a mathematical analysis has been carried out for the axial flow of a bingham plastic fluid, in the concentric cylinder viscometer which consists of a cylindrical sample holder (the cup) and a cylindrical spindle (the bob) coaxial with the cup. the fluid to be tested flows through the annular gap of the cup and the bob system, sheared by the rotation of the inner cylinder, while the outer cylind...

Success of a drilling, workover or completion fluid can be directly attributed to its viscosity at the shear rate of interest. In practice, fluids are subjected to a wide range of shear rates; therefore, a thorough understanding of fluid rheology and the impact of shear is necessary to optimize fluid design. Ideally, high viscosity is desirable only under low shear rate conditions, and should d...

We study the dynamics of shear-band formation and evolution using a simple rheological model. The description couples the local structure and viscosity to the applied shear stress. We consider in detail the Couette geometry, where the model is solved iteratively with the Navier-Stokes equation to obtain the time evolution of the local velocity and viscosity fields. It is found that the underlyi...

secondary flow investigation could be regarded as an important issue in open channel flow, in spite of its lower quantity compared to the base flow in the water course. it should be given special consideration because of the influence on some hydraulic factors in open channel, specifically in compound channels. in compound channels' due to the difference in the flow velocity of the main ch...

We study the rheological behavior of concentrated granular suspensions of simple spherical particles. Under controlled stress, the system exhibits an S-shaped flow curve (stress vs shear rate) with a negative slope in between the low-viscosity Newtonian regime and the shear thickened regime. Under controlled shear rate, a discontinuous transition between the two states is observed. Stress visua...

A theoretical connection between nonlinear shear viscosity and the long time tail of the equilibrium stress-stress correlation function is pointed out. The connection is a consequence of the Goddard-Miller rheological equation of state which takes into account the angular rotation of a fluid in steady uniform shear.

Large-amplitude oscillatory shear flow (LAOS) is a popular for studying the nonlinear physics of complex fluids. Specifically, the strain rate sweep (also called the strain sweep) is used routinely to identify the onset of nonlinearity. In this paper, we give exact expressions for the nonlinear complex viscosity and the corresponding nonlinear complex normal stress coefficients for the Oldroyd ...

OBJECTIVE To determine whether selectin-mediated leukocyte-rolling velocity in inflamed venules in vivo is determined by wall shear rate (WSR) or by wall shear stress (WSS). METHODS WSS was manipulated independently of WSR by altering the viscosity of blood plasma in mice with an isovolemic exchange of blood for low- or high-viscosity dextran solutions. Rolling of neutrophils or beads coated ...

Ultrarelativistic heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) are thought to have produced a state of matter called the quark-gluon plasma, characterized by a very small shear-viscosity to entropy-density ratio η/s, near the lower bound predicted for that quantity by AdS/CFT methods. As the produced matter expands and cools, it evolves through a phase described by a hadro...