non-newtonian fluid

Mathematical Modeling of Deposits Accumulation on the Plastic Biliary Stent Surface for Predicting Its Occlusion

Authors: Kuchumov A. G.

Endoprosthetics with plastic stents has been used to restore bile drainage through the percutaneous or endoscopic method since the late 1970s. The long-term results cannot be considered satisfactory due to the high incidence of jaundice recurrence which is caused by the occlusion of plastic stents with a biliary sludge (accumulation of cholesterol crystals, pigment crystals, bacteria and calcium salts). Cholesterol is considered to be the main component of biliary sludge that stimulates the reduction of the stent lumen. The average lifetime of stents is 3–6 months.

Double Layer of Polymer Melts in Channels of Dies

Authors: Snigerev B. A., Tazyukov F. K.

Numerical simulation of double-layer nonlinear viscous flow in channels of dies was performed. The fluid motion is described by equations conservation of mass and momentum, supplemented by the rheological equation of state of nonlinear viscous fluid on the Carreau model. The technique of numerical solve the problem based on the finite element method is described. Results the field of velocities, pressure, stresses, position the interface boundary of two-layer flow depending on rheological properties of liquid and flow regimes are presented.