One-dimensional modeling of steady frictional radial flow of a perfect gas through a high-pressure piezoelectrically actuated microvalve under low leak-rate conditions is studied. Focusing on the micro-scale gap between the boss and seat plates, a model was developed for axisymmetric flow between two thermally insulated, parallel disks flowing radially toward an outlet hole at the center of the...

Shapes of vesicles with toroidal topology are studied in the context of curvature models for the membrane. For two simplified curvature models, the spontaneous-curvature (SC) model and the bilayer-couple (BC) model, the structure of energy diagrams, sheets of stationary shapes and phase diagrams are obtained by solving shape equations for axisymmetric shapes. Three different sheets of axisymmet...

We construct a simple symplectic map to study the dynamics of eccentric orbits in non-spherical potentials. The map offers a dramatic improvement in speed over traditional integration methods, while accurately representing the qualitative details of the dynamics. We focus attention on planar, non-axisymmetric power-law potentials, in particular the logarithmic potential. We confirm the presence...

The performance of Joule-Thomson (JT) cryocoolers can be improved by introducing ejectors. Ejectors with various geometric features have been proposed and investigated for cryogenic cooling in earlier studies, but only limited research is done on ejectors a nozzle throat diameter less than 1 mm. In this paper, we present miniature ejector 162 ?m that was measured using X-ray computed tomography...

in this paper, an approximate axisymmetric method is developed which can reliably calculate fully viscous hypersonic flow over blunt-nosed bodies. in this method, a maslen’s second-order pressure expression is used instead of the normal momentum equation. the combination of maslen’s second-order pressure expression and viscous shock layer equations is developed to accurately and efficiently com...

A study of the three-dimensional axisymmetry-breaking instability of an axisymmetric convective #ow associated with crystal growth from bulk of melt is presented. Convection in a vertical cylinder with a parabolic temperature pro"le on the sidewall is considered as a representative model. The main objective is the calculation of critical parameters corresponding to a transition from the steady ...

In this paper an upwind algorithm based on Roe’s scheme is presented for solution of PNS equations. Non iterative-implicit method using finite volume technique is used. The main advantage of this approach, in comparison with similar upwind methods, is reduction of oscillations around sonic line. This advantage causes the present method to be able to analyze supersonic flows with free stream Mac...

In this study, two-dimensional electro-mechanical analysis of a composite rotating shaft subjected to non-axisymmetric internal pressure and applied voltage is investigated where hollow piezoelectric shaft reinforced by boron nitride nanotubes (BNNTs). Composite structure is modeled based on piezoelectric fiber reinforced composite (PFRC) theory and a representative volume element has been cons...

The generation of solar non-axisymmetric magnetic fields is studied based on a linear α −Ω dynamo model in a rotating spherical frame. The model consists of a solarlike differential rotation, a magnetic diffusivity varied with depth, and three types of α-effects with different locations, i.e. the tachocline, the whole convective zone and the sub-surface. Some comparisons of the critical α-value...

This paper investigates the effect of inserting a ring type barrier on leakage flow of brush seals with different bristles clearances (the distance between bristle pack tip and rotor surface). The ring is placed on both upstream and downstream sides of the bristles. An axisymmetric CFD model is employed to calculate radial pressure distribution along backing plate, axial pressure variation on r...