Azimuthal magnetorotational instability is a mechanism that generates nonaxisymmetric field pattern. Nonlinear simulations in an infinite Taylor-Couette system with current-free external field show, that not only the linearly unstable mode m = 1 appears, but also an inverse cascade transporting energy into the axisymmetric field is possible. By varying the Reynolds number of the flow and the Ha...

I present an extension of the thin layer approximation to non-axisymmetric bow shocks. By choosing a suitable set of curvilinear coordinates that matches the geometry of a generally distorted bow shock surface, I derive the fluid equations for the flow. Analytical expansions are given for the matter flow near the bow shock stagnation point. Numerical solutions are also obtained, by using a revi...

We study the creeping flow of a dilute, monodisperse polystyrene/oligomeric styrene Boger fluid through axisymmetric abrupt contraction-expansions of various contraction ratios and over a wide range of Deborah numbers. Measurements of the entry pressure drop for the polystyrene solution increase monotonically with Deborah number and are substantially larger than those observed for a similar New...

The motion of tracer particles used for visualization in a steady axisymmetric swirling flow in a closed rotating disk–cylinder system is studied numerically. It is assumed that there exists a density mismatch between the particles and the fluid. It is shown that such a slight density mismatch leads to a deviation of the particle motion from steady axisymmetric streamlines, which in its turn yi...

We show that suitable initial disturbances to steady or long-period pulsatile flows in a straight tube with an axisymmetric 75%-occlusion stenosis can produce very large transient energy growths. The global optimal disturbances to an initially axisymmetric state found by linear analyses are three-dimensional wave packets that produce localized sinuous convective instability in extended shear la...

In this paper we examine the effect of mild stenosis on blood flow, in an irregular axisymmetric artery with oscillating pressure gradient. The Herschel-Bulkley fluid model has been utilized for this study. The combined influence of an asymmetric shape and surface irregularities of constriction has been explored in this computational study. An extensive quantitative analysis has been performed ...

We present a numerical scheme for axisymmetric solutions to curvature driven moving boundary problems governed by a local law of motion, e.g. the mean curvature flow, the surface diffusion flow, and the Willmore flow. We then present several numerical experiments for the Willmore flow. In particular, we provide numerical evidence that the Willmore flow can develop singularities in finite time.

T HE life cycle of engineering design involves innovating to introduce a product, and when that is done, looking for ways to make itwork better. Supersonic aerodynamics can be looked atwith a similar perspective. Man has always wanted to fly faster. While the basicmechanics of supersonic flightwas laid out in the 1950s, people are yet to find ways in which to make Supersonic flight more efficie...

This paper studies a steady axisymmetric flow in a constricted rigid tube. A shear-thinning fluid modelling the deformation-dependent viscosity of the blood is proposed. The motion equation is written in vorticity-streamfunction formulation and is solved numerically by a finite difference scheme. The flow pattern with the distributions of pressure and shear stress at the wall are computed. The ...

Front tracking has proved to be an accurate and efficient algorithm in the sense that tracking the interface can reduce the error significantly [9,10]. By applying this algorithm, we conduct numerical simulations of Richtmyer–Meshkov (RM) instabilities in spherical geometry for axisymmetric flow. We demonstrate scaling invariance with respect to shock Mach number for fluid mixing statistics, su...