Numerical and Experimental Analyses of Shear-thinning Viscoelastic Fluid Flow in Confined Geometries

This thesis focuses on numerical and experimental investigations of shear-thinning viscoelastic (VE) fluid flow in confined geometries, such as porous media and microchannels for applications in polymer processing, heat transfer devices, biological and biomedical systems, and enhanced oil recovery. The numerical research focuses on the hydrodynamic performance of a VE fluid with particular attention to vortex patterns that develop downstream of smooth contractions/expansions. It was found that there are critical regions, in which the behavior of VE fluid flow is subjected to a change through different pore geometries. The experimental work focuses on the retention phenomenon of hydrolyzed polyacrylamide polymers, using microfluidic chips in which the effect of single pore size on retention is measured. From these experiments, the contribution of different retention mechanisms was reported through different sizes of microchannel. It was found that polymer orientation plays a role in the measured absolute and relative adsorption in different concentrations

Dynamic Modelling of Axle Tramp in a Sport Type Car

One of the most significant dynamic aspects of coupled vibration of transmission system and dependent type suspension systems is axle tramp. The tramp is defined as undesirable oscillation of rigid live axle around roll axis. In spite of utilizing powerful engines in some type of sport cars, tramp occurrence causes loss of longitudinal performance. The aim of this paper is to derive a mathematical model for predicting and classifying of the tramp. A parameter study reveals that, some parameters such as engine torque, moving parts moment of inertia, car and wheels weight and the material used in suspension system play important role in controlling the tramp. It is shown that large difference between sprung and unsprung mass moment of inertia around the roll-axis, low vehicle mass, short rear track and medium damping values have significant effects on the severity of tramp

Dynamic modelling of axle tramp in a sport type car

Abstract. One of the most significant dynamic aspects of coupled vibration of transmission system and dependent type suspension systems is axle tramp. The tramp is defined as undesirable oscillation of rigid live axle around roll axis. In spite of utilizing powerful engines in some type of sport cars, tramp occurrence causes loss of longitudinal performance. The aim of this paper is to derive a mathematical model for predicting and classifying of the tramp. A parameter study reveals that, some parameters such as engine torque, moving parts moment of inertia, car and wheels weight and the material used in suspension system play important role in controlling the tramp. It is shown that large difference between sprung and unsprung mass moment of inertia around the roll-axis, low vehicle mass, short rear track and medium damping values have significant effects on the severity of tramp