The purpose of this study was to determine the influence of radial motion of an arterial wall on the shear stress that flowing blood imposes on the wall (wall shear stress). Wall shear stress is known to influence endothelial cell function and may play a role in atherogenesis, but its magnitude and distribution in the circulation are not well understood. To simulate arterial wall motion, we use...

This paper is intended to evaluate the wall effects in the pure-drag case of plane cavity flow past an arbitrary body held in a closed tunnel, and to establish a n accurate correction rule. The three theoretical models in common use, namely, the open-wake, Riabouchinsky and re-entrant-jet models, are employed t o provide solutions in the form of some functional equations. From these theoretical...

Altered perfusion of the bronchial mucosal plexus relative to the adventitial plexus may contribute to geometric changes in the airway wall and lumen. We studied bronchial perfusion distribution in sheep by using fluorescent microspheres at baseline and during intrabronchial artery challenge with methacholine chloride (MCh; n = 7). Additionally, we measured airway resistance (Raw) during MCh wi...

A mathematical model of microbial growth for limiting nutrients in a fully three dimensional flow reactor which accounts for the colonization of the reactor wall surface by the microbes is studied analytically. It can be viewed as a model of the large intestine or of the fouling of a commercial bioreactor or pipe flow. Two steady state regimes are identified, namely, the complete washout of the...

In the construction process of a plastic concrete cut-off wall, concreting is usually performed using the termie pipe method. In this method, concreting is performed from the lowest point in the excavated trench (containing the slurry) using a funnel and the pipe connected to it. The concrete poured in the funnel gradually settles in the panel through the termie pipe which is beneath the slurry...

The predilection of atherosclerotic lesions for specific sites in the arterial tree is believed to be related t o the wall shear stress, exerted by the blood flow. Measurement of the magnitude of the wall shear stress is difficult and is frequently determined by an extrapolation of the velocity field t o find the wall shear rate and an estimation of the viscosity of the fluid in the neighborhoo...

OBJECTIVES To elucidate the role of fluid mechanical factors in the localized genesis and development of atherosclerotic lesions in man. METHODS Flow patterns and preferred sites of atherosclerotic lesions in the human aortic arch were studied in detail using isolated transparent aortic trees prepared from humans postmortem and by means of flow visualization of tracer polystyrene microspheres...

Introduction: Generally, geometrical parameters of the cyclone have a profound effect on determining its performance. The air outlet (Vortex Finder) as one of the cyclone’s components has a significant impact on the cyclone’s internal flow pattern, pressure drop and even dust removal efficiency. Material and Methods: Two different air outlets were designed in order to be easily installed and r...

The indicator-fractiomition technic for measurement of regional blood flow has been applied to the measurement of blood flow in the aortic wall, using Rb. The aorticindicator content declines slowly with time during the first minute, which shows that the aorta has a smaller extraction ratio for Rb than the rest of the body. The application of the indieator-fractionation teehnic when organ conte...