9,695 research outputs found
Peristaltic Pumping of Blood Through Small Vessels of Varying Cross-section
The paper is devoted to a study of the peristaltic motion of blood in the
micro-circulatory system. The vessel is considered to be of varying
cross-section. The progressive peristaltic waves are taken to be of sinusoidal
nature. Blood is considered to be a Herschel-Bulkley fluid. Of particular
concern here is to investigate the effects of amplitude ratio, mean pressure
gradient, yield stress and the power law index on the velocity distribution,
streamline pattern and wall shear stress. On the basis of the derived
analytical expression, extensive numerical calculations have been made. The
study reveals that velocity of blood and wall shear stress are appreciably
affected due to the non-uniform geometry of blood vessels. They are also highly
sensitive to the magnitude of the amplitude ratio and the value of the fluid
index.Comment: Accepted for publication in ASME journal of Applied Mechanics. arXiv
admin note: text overlap with arXiv:1108.1285v
Peristaltic Transport of a Rheological Fluid: Model for Movement of Food Bolus Through Esophagus
Fluid mechanical peristaltic transport through esophagus has been of concern
in the paper. A mathematical model has been developed with an aim to study the
peristaltic transport of a rheological fluid for arbitrary wave shapes and tube
lengths. The Ostwald-de Waele power law of viscous fluid is considered here to
depict the non-Newtonian behaviour of the fluid. The model is formulated and
analyzed with the specific aim of exploring some important information
concerning the movement of food bolus through the esophagus. The analysis has
been carried out by using lubrication theory. The study is particularly
suitable for cases where the Reynolds number is small. The esophagus is treated
as a circular tube through which the transport of food bolus takes places by
periodic contraction of the esophageal wall. Variation of different variables
concerned with the transport phenomena such as pressure, flow velocity,
particle trajectory and reflux are investigated for a single wave as well as
for a train of periodic peristaltic waves. Locally variable pressure is seen to
be highly sensitive to the flow index `n'. The study clearly shows that
continuous fluid transport for Newtonian/rheological fluids by wave train
propagation is much more effective than widely spaced single wave propagation
in the case of peristaltic movement of food bolus in the esophagus.Comment: Accepted for publication in Applied Mathematics and Mechanics (AMM),
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