in this study prediction of the steady-state flow of branched polymer melts in pipe geometry with finite volume method is presented. our analysis in this study revealed that;for normal-stress tqq , the xpp model can predict this tensor unlike the other viscoelastic models such as ptt or gieskus which can not predict tqq for viscoelastic fluid in two dimensional pipe flows. the fluid is modelled...

in industry, flow instabilities are important in journal bearings at high rotational speeds. for inviscid flows between two rotating coaxial cylinders, an instability criterion was introduced by taylor-couette. however, viscosity may play as stabilizer or destabilize in such flows. in this work, stability theories were reviewed for two coaxial rotating cylinders. then, flow instability patterns...

OBJECTIVES This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. MATERIAL AND METHODS A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For th...

Composite restorations are popular because of their superior esthetics and acceptable clinical performance. But shrinkage is still a drawback. Polymerization shrinkage results in volumetric contraction, leading to deformation of the cusps, microleakage, decrease of marginal adaptation, enamel micro-cracks and postoperative sensitivity. A new class of ring opening resin composite based on silora...

analysis of non-laminar flows in coarse alluvial beds has a wide range of applications in various civil engineering, oil and gas, and geology problems. darcy equation is not valid to analyze transient and turbulent flows, so non-linear equations should be applied. non-linear equations are classified into power and binomial equations. binomial equation is more accurate in a wide range of velocit...

investigating nozzle’s orifice flow is challenging both experimentally and theoretically. this paper focuses on simulating flow inside diesel injector nozzle via ansys fluent v15. validation is performed with experimental results from winkhofler et al (2001). several important parameters such as mass flow rate, velocity profiles and pressure profiles are used for this validation. results includ...

in this paper the heating process in a box annealing unit is simulated and the effect of various parameters involved in the process is examined. for this purpose, the full naiver-stokes equations along with the standard k- turbulence model are solved in the fluid region using the finite volume approach. in the solid area the conduction heat transfer equation is employed using approporate surfac...