Motivated by recent event studies and modeling efforts on pulsating aurora, which conclude that the precipitation energy during these events is high enough to cause significant chemical changes in the mesosphere, this study looks for the bulk behavior of auroral pulsations. Based on about 400 pulsating aurora events, we outline the typical duration, geomagnetic conditions, and change in the pea...

The global entropy generation rate in the zero-mean oscillatory flow of a Maxwell fluid in a pipe is analyzed with the aim of determining its behavior at resonant flow conditions. This quantity is calculated explicitly using the analytic expression for the velocity field and assuming isothermal conditions. The global entropy generation rate shows well-defined peaks at the resonant frequencies w...

Abstract. We study flow-induced enhancement of the speed of pulsating traveling fronts for reaction-diffusion equations, and quenching of reaction by fluid flows. We prove, for periodic flows in two dimensions and any combustion-type reaction, that the front speed is proportional to the square root of the (homogenized) effective diffusivity of the flow. We show that this result does not hold in...

We describe and analyze the flow dynamics in replicas of a human anterior communicating artery aneurysm. The replicas were placed in a circuit of pulsating non-Newtonian fluid, and flows were adjusted to replicate human physiologic parameters. Individual slipstreams were opacified with isobaric dyes, and images were recorded on film and by CT/MR angiography. When flow in the afferent (internal ...

In recent years, flexible pipes made of synthetic polymer materials are being rapidly introduced into practice. Pulsating currents important in driving water and other liquids main pipes. This paper examines the pulsating a viscous incompressible fluid an elastic pipe. The necessary hydrodynamic parameters will be determined by solving problem, such as distributions pressure, velocity, flow rat...

SUMMARY A replica of a lethal wide-necked basilar artery aneurysm was created by casting a deceased patient's brain vessels and then placing the replica in a circuit of pulsating optically clear non-Newtonian fluid. Individual fluid slipstreams were opacified with isobaric dyes, and images were recorded on film. Studies were completed on the vascular replica, then were repeated, first after pla...

A replica of a lethal wide-necked basilar artery aneurysm was created by casting a deceased patient’s brain vessels and then placing the replica in a circuit of pulsating optically clear non-Newtonian fluid. Individual fluid slipstreams were opacified with isobaric dyes, and images were recorded on film. Studies were completed on the vascular replica, then were repeated, first after placement o...