نتایج جستجو برای: Wall shear stress

تعداد نتایج: 647164  

This study makes use of the Tsallis entropy to predict the shear stress distribution. Given a definition of the Tsallis entropy, it is maximized by using the probability density function, which then is used to attain a novel shear stress equation. This is then employed for calculating the shear stress distribution in rectangular channels in different aspect ratios and finally, for viability, th...

1997
Henry G. Nepomuceno Richard M. Lueptow

The fluctuating wall shear stress, wall pressure, and streamwise velocity were measured simultaneously in a cylindrical boundary layer at a momentum thickness Reynolds number of Reu52160 and a boundary layer thickness to cylinder radius ratio of d/a55 using a hot wire wall shear stress probe mounted just upstream of a hearing aid microphone and a hot wire velocity probe. Variable Interval Time ...

Journal: :Stroke 2003
Satoshi Tateshima Yuichi Murayama J Pablo Villablanca Taku Morino Kiyoe Nomura Kazuo Tanishita Fernando Viñuela

BACKGROUND AND PURPOSE Little attention has been focused on the role of fluid-induced wall shear stress in fully developed cerebral aneurysms. The purpose of this study is to evaluate the alternation and distribution of wall shear stress over 1 cardiac cycle in patients' aneurysms. METHODS A middle cerebral artery aneurysm and a basilar tip aneurysm with localized outpouching (blebs) in their...

2005
Martin Klanchar John M. Tarbell Da-Ming Wang

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...

Journal: :journal of biomedical physics and engineering 0
z. mortazavinia department of mechanical engineering, écolepolytechnique de montréal, montreal, canada e. goshtasbi rad school of mechanical engineering, shiraz university, shiraz, iran h. emdad school of mechanical engineering, shiraz university, shiraz, iran m. b. sharifkazemi shiraz medical school, shiraz university of medical science, shiraz, iran a. zare department of mechanical engineering, islamic azad university, shiraz branch, member of young researchers club, shiraz, iran a. r. mehdizadeh center for research in medical physics and engineering, school of medicine, shiraz university of medical science, shiraz, iran

background: the interaction between the blood and the vessel wall is of great clinical interest in studying cardiovascular diseases, the major causes of death in developed countries. objective: to understand the effects of incorporating fluid-structure interaction into the simulation of blood flow through an anatomically realistic model of abdominal aorta and renal arteries reconstructed from c...

Journal: :Journal of biomechanics 1998
C R Ethier D A Steinman X Zhang S R Karpik M Ojha

PURPOSE Restenosis due to distal anastomotic intimal hyperplasia, a leading cause of arterial bypass graft failure, is thought to be promoted by hemodynamic effects, specifically 'abnormal' wall shear stress patterns. The purpose of this study was to quantify the effects of flow waveform on peri-anastomotic flow and wall shear stress patterns. METHODS Blood flow and wall shear stress patterns...

Journal: :Hypertension 1999
C Carallo C Irace A Pujia M S De Franceschi A Crescenzo C Motti C Cortese P L Mattioli A Gnasso

The localization of atherosclerotic lesions is influenced by hemodynamic factors, namely, shear stress and tensive forces. The present study investigated the relationships between shear stress and circumferential wall tension and between these hemodynamic factors and the intima-media thickness (IMT) of the common carotid artery in healthy men. Fifty-eight subjects were studied. Shear stress was...

Journal: :Kidney international 2008
Mahesh K Krishnamoorthy Rupak K Banerjee Yang Wang Jianhua Zhang Abhijit Sinha Roy Saeb F Khoury Lois J Arend Steve Rudich Prabir Roy-Chaudhury

Venous stenosis is a significant problem in arteriovenous fistulae, likely due to anatomical configuration and wall shear stress profiles. To identify linkages between wall shear stress and the magnitude and pattern of vascular stenosis, we produced curved and straight fistulae in a pig model. A complete wall stress profile was calculated for the curved configuration and correlated with luminal...

Journal: :AJNR. American journal of neuroradiology 2008
L-D Jou D H Lee H Morsi M E Mawad

BACKGROUND AND PURPOSE Hemodynamics is often recognized as one of the major factors in aneurysm rupture. Flow impingement, greater pressure, and abnormal wall shear stress are all indications for aneurysm rupture. Characterizing wall shear stress for intracranial aneurysms at similar anatomic locations may help in understanding its role. MATERIALS AND METHODS Twenty-six intracranial aneurysms...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2011
majid ahmadlouie darab farzan ghalichi,

in this theoretical study, the effect of various types of bypass graft angles on the flow field, has been investigated specially on the temporal wall shear stress (wss) on the toe, heel and some locations on the bed of the left anterior descending (lad) artery at the anastomoses areas in the aorto-coronary (ac) and coronary-coronary (cc) bypasses. flow fields in both bypasses with angles of 20º...

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