INTRODUCTION Restenosis is strongly attributed to stresses caused by stent-artery interactions generated in the artery after balloon angioplasty. Numerical methods are often used to examine the stent-artery mechanical interactions. To overcome the extensive computational requirements demanded by these simulations, simplifications are needed. OBJECTIVE We introduce simplified models to calcula...

The forcing term in the lattice Boltzmann equation (LBE) is usually used to mimic Navier-Stokes equations with a body force. To derive axisymmetric model, forcing terms are incorporated into the two-dimensional (2D) LBE to mimic the additional axisymmetric contributions in 2D Navier-Stokes equations in cylindrical coordinates. Many axisymmetric lattice Boltzmann D2Q9 models were obtained throug...

In this paper, the cell-centered finite volume method (CC-FVM) has been presented to simulate the axisymmetric radial flow toward a pumping well. The model is applied to the unstructured triangular grids which allows to simulate inhomogeneous and complex-shaped domains. Due to the non-orthogonality of the irregular grids, the multipoint flux approximation (MPFA) methods are used to discretize t...

Noise generation in a subsonic round jet is studied by a simplified model, in which nonlinear interactions of spatially evolving instability modes lead to the radiation of sound. The spatial mode evolution is computed using linear parabolized stability equations. Nonlinear interactions are found on a mode-by-mode basis and the sound radiation characteristics are determined by solution of the Li...

We develop a theoretical model of surface-tension-driven, three-dimensional instabilities of liquid-lined elastic tubes—a model for pulmonary airway closure. The model is based on large-displacement shell theory, coupled to the equations of lubrication theory, modified to ensure the exact representation of the system’s equilibrium configurations. The liquid film that lines the initially uniform...

Recently, Halliday et al. presented an idea by inserting the “source” terms into the two-dimensional (2D) lattice Boltzmann equation (LBE) so that the emergent dynamics of the lattice fluid can be transformed into the cylindrical polar system. This paper further extends the idea of Halliday et al. to include the effect of azimuthal rotation. The terms related to the azimuthal effect are conside...

We present an analysis of the primary bifurcations that occur in a mathematical model that uses the (three-dimensional) Navier-Stokes equations in the Boussinesq approximation to describe the flow of a near unity Prandtl number fluid (i.e. air) in the differentially heated rotating annulus. In particular, we investigate the double Hopf (Hopf-Hopf) bifurcations that occur along the axisymmetric ...

2-d and axisymmetric navier-stokes equations are solved using reiman-roe solver with different limiters for second-order accurate schemes. the results were obtained for supersonic viscous flows over semi-infinite axisymmetric and 2-d bodies. the free stream mach numbers were 7.78 and 16.34. the stability of roe method with different limiters and entropy conditions were considered. the results s...

A recent paper claims that the well known Cowling ‘anti-dynamo’ theorem is a “misconception”, and that a simple axisymmetric sunspot model constitutes a counter example. We do not believe these claims to have been substantiated.

ABSTRACT Macrosegregation has been received high attention in the solidification modeling studies. In the present work, a numerical model was developed to predict the macrosegregation during the DC Casting of an Al-4.5wt%Cu billet. The mathematical model developed in this study consists of mass, momentum, energy and species conservation equations for a two-phase mixture of liquid and solid in a...