Simulation of scour-pit formations under the bridge decks and around the bridge piers, due to sediment suspension and transport caused by flooding and pressure flow conditions, is of significant interest nowadays to computational fluid dynamics (CFD) and hydraulic researchers. From CFD perspective, analysis of bridge under various flooding conditions and impact of the drag and lift forces on it...

It has been known that there is a viscoelastic instability in the channel flow past a cylinder at high Deborah (De) number. Some of our numerical simulations and a boundary layer analysis indicated that this instability is related to the shear flow in the gap between the cylinder and the channel walls in our previous work. The critical condition for instability initiation may be related to an i...

Platelet functions are increasingly measured under flow conditions to account for blood hydrodynamic effects. Typically, these studies involve exposing platelets to high shear stress for periods significantly longer than would occur in vivo. In the current study, we demonstrate that the platelet response to high shear depends on the duration of shear exposure. In response to a 100 dyn/cm2 shear...

The stability of one liquid thread immersed in a fluid in a shear field is considered by linear stability analysis. A constant shear stress is imposed far away from the thread. The shear flow tends to deform and elongate the thread. The stability of the thread is characterized by the growth rate of a random perturbation. The equation for the growth rate leads to an eigenvalue problem with the w...

Mammalian cells have been widely used in bioreactors to produce biological products such as pharmaceutical materials. The productivity of such bioreactors is vastly affected by flow-induced cell damage in complicated flow environments, such as agitation-driven turbulence and oxygen bubble bursting at the interface between the culturing medium and air. However, there is no systematic approach to...

The problem of blood flow through an overlapping constriction in arteries is investigated in this work. To account for the non-Newtonian behavior and the peripheral layer, blood has been represented by a two-fluid model, consisting of a core region of suspension of all the erythrocytes assumed to be a Casson fluid and a peripheral layer of plasma (Newtonian fluid). The expression for the flow c...

Fluid shear stress alters the morphology and function of the endothelium by activating several kinases. Furthermore, shear stress potently inhibits apoptosis of endothelial cells. Since activation of Akt kinase has been shown to prevent cell death, we investigated the effects of shear stress on Akt phosphorylation. To test the hypothesis that shear stress interacts with the Akt kinase pathway, ...

We investigated the effects of particle shape on shear thickening in densely packed suspensions. Rods of different aspect ratios and nonconvex hooked rods were fabricated. Viscosity curves and normal stresses were measured using a rheometer for a wide range of packing fractions for each shape. Suspensions of each shape exhibit qualitatively similar discontinuous shear thickening. The logarithmi...

We study the shearing rheology of dense suspensions of elastic capsules, taking aggregation-free red blood cells as a physiologically relevant example. Particles are non-Brownian and interact only via hydrodynamics and short-range repulsive forces. An analysis of the different stress mechanisms in the suspension shows that the viscosity is governed by the shear elasticity of the capsules, where...