In flooded evaporators, refrigerants are boiling outside the tubes. This paper focuses on the bubbly two-phase flow characteristics in twisted tube bundles. The quasi 3-D high speed video method and computational fluid dynamics are carried out to understand the effects which angles between the major axis of the cylinder and vertical direction ( ) and bubble diameters have on the motion behavio...

Using complex variable methods and conformal mapping techniques, we establish the existence of coated cavities of various shapes that do not disturb the warping function in a host elliptical bar. These cavities are known as ‘partly neutral cavities’. Our results show that the two axes corresponding to the neutral elliptical coating are parallel to those of the host elliptical bar and that the c...

Abstract-An alternating method, in conjunction with the finite element method and a solution for multiple coplanar elliptical cracks in an intinite solid, is used to determine stress intensity factors for semi-elliptical surface flaws in cylindrical pressure vessels. The solution technique for multiple cracks in an infinite body has recently been developed by the prese.nt authors which implemen...

Concrete filled tube (CFT) columns have been used as primary axial load-carrying members in high-rise building especially in seismic zones. The structural member has become popular as it has a number of distinct advantages over an equivalent steel, reinforced concrete, or steel-reinforce concrete structural member. This paper is intended to presents numerical modeling of elliptical concrete-fil...

In this paper, the problems of composite-patch repair of (i) center and edge-cracked panels loaded in the far-field; and (il) cracks emanating from pin-loaded fastener holes, are examined in thorough detail. The effects of various non-dimensional design parameters on the reduction in the stress-mtensity factors near the crack-tip are determined, and are presented in the form of design charts. B...

A chemostat with two organisms competing for a single growthlimiting nutrient controlled by feedback-mediated dilution rate is analyzed. A specific feedback function is constructed which yields circular and elliptical periodic orbits for the limiting system. A theorem on the stabilization of periodic orbits in conservative systems is developed and for a given elliptical orbit, the result is use...

Abstaact-Mercier’s localized perturbation criterion near the magnetic axis is examhied for a particular type of toroidal configuration of non-planar magnetic axis of variable curvature and torsion with non-circular (elliptically and triangularly deformed) plasma cross section for the ‘resonance case’. As an application, a numerical calculation is carried out for a class of equilibria that belon...