Electrorheological fluids are smart materials that are concentrated suspensions of polarizable particles in a nonconducting dielectric liquid. In moderately large electric fields the particles form chains along the field lines and these chains then aggregate into the form of columns. These chainlike and columnar structures yield dramatic changes in the rheological properties of the suspensions....

Magnetorheological (MR) fluids are substances that respond to an applied magnetic field with a change in their rheological behavior. Though they are functionally similar to electrorheological (ER) fluids, MR fluids exhibit much higher yield strengths for applied magnetic fields than ER fluids for applied electric fields. The devices using MR fluids have an ability to provide high-torque, low-in...

I. Fluid Rheology In this note (I of IV) we summarize the rheological properties of the test fluid in shear and extension. The viscoelastic fluid consists of an 0.025 wt% solution of monodisperse polystyrene (PS) (Scientific Polymer Products, Inc.) with a polydispersity of 1.03. The polystyrene is dissolved in oligomeric styrene (Hercules Piccolastic A5) to yield a dilute solution with c/c* = 0...

An enhanced version of the flexure-based microgap rheometer (FMR) is described which enables rheological measurements in steady state shearing flows of bulk fluid samples of PDMS with an absolute gap separation between the shearing surfaces of 100 nm – 100 μm. Alignment of the shearing surfaces to a parallelism better then 10 rad allows us to reliably measure shear stresses at shear rates up to...

The objective of much fluidisation research has been the prediction of industrial beds, which are often large and operated at high pressure and temperature. This may be achieved through the use of Eulerian two-fluid models. Two such models have been compared with experimental results of the structure of a jet in a bubbling fluidised bed. In the first two-fluid model the particles are treated as...

National Institute of Standards and Technology, Gaithersburg, MD 20899-0001 The rheological or flow properties of concrete in general and of high performance concrete (HPC) in particular, are important because many factors such as ease of placement, consolidation, durability, and strength depend on the flow properties. Concrete that is not properly consolidated may have defects, such as honeyco...

In this study, the immersed boundary-thermal lattice Boltzmann method has been used to simulate non-Newtonian fluid flow over a heated circular cylinder. The direct-forcing algorithm has been employed to couple the off-lattice obstacles and on-lattice fluid nodes. To investigate the effect of boundary sharpness, two different diffuse interface schemes are considered to interpolate the velocity ...

We present computational fluid dynamic (CFD) simulation of aggregation of two deformable cells in a shearflow. This work is motivated by an attempt to develop computational models of aggregation of red blood cells (RBCs). Aggregation of RBCs is a major determinant of blood viscosity in microcirculation under physiological and pathological conditions. Deformability of the RBCs plays a major role...

A metamaterial structure formed by foamed metal and starch and oil-based electrorheological (ER) fluid is designed in this paper. Experiments show that the metamaterial structure exhibits a regulation effect on the amplitude and phase of the transmitted waves of 35–80 kHz ultrawideband ultrasonic waves in water. With the increase of the electric field, the transmission amplitude and phase of th...

Secondary settling tanks (SSTs) are the most hydraulically sensitive unit operations in biological wastewater treatment plants. The maximum permissible inflow to the plant depends on the efficiency of SSTs in separating and thickening the activated sludge. The flow conditions and solids distribution in SSTs can be predicted using computational fluid dynamics (CFD) tools. Despite extensive studi...