One strategy for reducing US dependence on petroleum is to develop new combustion technologies for burning the fuel-lean mixtures of hydrogen or hydrogen-rich syngas fuels obtained from the gasification of coal and biomass. Fuel-flexible combustion systems based on lean premixed combustion have the potential for dramatically reducing pollutant emissions in transportation systems, heat and stati...

We are concerned here with confined, axisymmetric flows of small viscosity driven by a prescribed Lorentz force. In a previous paper we examined the case where the body force is purely azimuthal, generating a swirling motion. We showed that, in such cases, Ekman pumping provides the means by which the flow establishes a steady state. In this paper we examine a problem which, superficially, look...

A simple inviscid model to predict the onset of breakdown in an axisymmetric vortex is proposed. Three problems are considered: the shock-induced breakdown of a compressible vortex, the breakdown of a free compressible vortex, and the breakdown of a free incompressible vortex. The same physical reasoning is used in all three problems to predict the onset of breakdown. It is hypothesized that br...

The egg of the frog Xenopus is cylindrically symmetrical about its animal-vegetal axis before fertilization. Midway through the first cell cycle, the yolky subcortical cytoplasm rotates 30 degrees relative to the cortex and plasma membrane, usually toward the side of the sperm entry point. Dorsal embryonic structures always develop on the side away from which the cytoplasm moves. Details of the...

With a view to understanding the air-fuel mixing behavior and the effects of the mixture quality on the emissions formation and engine performance, a new quantitative factor of the in-cylinder air-fuel homogeneity named Homogeneity Factor (HF) has been developed. Its characteristics under various injection conditions and air swirl motions within the cylinder have been investigated with CFD simu...

This paper presents a swirl-shaped microfeatured ionic polymer-metal composite (IPMC) actuator. A novel micromachining process was developed to fabricate an array of IPMC actuators on a glass substrate and to ensure that no shortcircuits occur between the electrodes of the actuator. We demonstrated a microfluidic scheme in which surface tension was used to construct swirl-shaped planar IPMC dev...

During a fruit-fly egg cell’s early development, its internal fluid begins to swirl in vortex—a transition caused by the coordinated behavior of elastic filaments cell.

This work is a continuation of experimental and computational studies of the internal flow field of a large-scale Danfoss atomizer presented at an earlier ILASS conference [1,2]. Fluent 6.1 is used to simulate the flow through the large-scale atomizer. The two-phase flow is modeled using three approaches: 1) a volume of fluid (VOF) method using a laminar flow assumption, 2) a VOF method using l...

We identified 6 genes that are essential for specifying ventral regions of the early zebrafish embryo. Mutations in these genes cause an expansion of structures normally derived from dorsal-lateral regions of the blastula at the expense of ventrally derived structures. A series of phenotypes of varied strengths is observed with different alleles of these mutants. The weakest phenotype is a redu...

Droplet transport processes that occur in fuel sprays and spray flames were examined using laser velocimetry, phase Doppler interferometry, and laser sheet beam photography. Droplet size and velocity (axial and radial) distributions were obtained in a swirl-stabilized, pressure-atomized kerosene spray under nonburning and burning conditions. The results show that the introduction of swirl to th...