Wall-shear stress patterns of coherent structures in turbulent duct flow

2009 ◽  
Vol 633 ◽  
pp. 147-158 ◽  
Author(s):  
SEBASTIAN GROSSE ◽  
WOLFGANG SCHRÖDER
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Wall Shear Stress ◽  
Coherent Structures ◽  
Shear Stress Distribution ◽  
Duct Flow ◽  
Wall Shear Stress Distribution ◽  
Wall Shear ◽  
Turbulent Duct Flow ◽  
Low Shear

The wall-shear stress distribution in turbulent duct flow has been assessed using the micro-pillar shear-stress sensor MPS3. The spatial resolution of the sensor line is 10.8l+(viscous units) and the total field of view of 120l+along the spanwise direction allows to capture characteristic dimensions of the wall-shear stress distribution at sufficiently high resolution. The results show the coexistence of low-shear and high-shear regions representing ‘footprints’ of near-wall coherent structures. The regions of low shear resemble long meandering bands locally interrupted by areas of higher shear stress. Conditional averages of the flow field indicate the existence of nearly streamwise counter-rotating vortices aligned in the streamwise direction. The results further show periods of very strong spanwise wall-shear stress to be related to the occurrence of high streamwise shear regions and momentum transfer towards the wall. These events go along with a spanwise oscillation and a meandering of the low-shear regions.

Effects of Cardiovascular Stent Design on Wall Shear Stress Distribution in Straight and Curved Arteries

2013 ◽  
Vol 284-287 ◽  
pp. 1642-1646
Author(s):  
Hao Ming Hsiao ◽  
Ying Chih Liao ◽  
Chien Han Lin ◽  
Fang Yu Liu ◽  
Yu Ming Tsuei
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Wall Shear Stress ◽  
Shear Stress Distribution ◽  
Stent Design ◽  
Wall Shear Stress Distribution ◽  
Cardiovascular Stent ◽  
Low Shear Stress ◽  
Wall Shear ◽  
Low Shear

he stent is a major breakthrough in the treatment of coronary artery diseases. The permanent vascular implant of a stent, however, changes the intra-stent blood hemodynamics. There is a growing consensus that the stent implant may change the artery wall shear stress distribution and therefore trigger the restenosis process. Several studies have suggested that low shear stress, particularly the shear stress less than 5 dyne/cm2, may lead to endothelial proliferation of smooth muscle cells. Computational fluid dynamics (CFD) has been widely used to analyze hemodynamics in stented arteries. In this paper, CFD models were developed to investigate the effects of cardiovascular stent design on the wall shear stress distribution in straight and curved arteries. Results show that the stent design pattern alone did not have a significant impact on the stent hemodynamics; however, stenting in curved arteries increased the low shear stress area which may lead to higher restenosis rate. The low shear stress area was almost doubled when the degree of artery curvature increased from 0o to 90o. The proposed methodology and findings will provide great insight for future optimization of stent design to reduce the risk of restenosis.

scholarly journals Wall Shear Stress Distribution of Small Aneurysms Prone to Rupture

Stroke ◽  
2014 ◽  
Vol 45 (1) ◽  
pp. 261-264 ◽  
Author(s):  
Vitor Mendes Pereira ◽  
Olivier Brina ◽  
Philippe Bijlenga ◽  
Pierre Bouillot ◽  
Ana Paula Narata ◽  
...  
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Wall Shear Stress ◽  
Shear Stress Distribution ◽  
Wall Shear Stress Distribution ◽  
Wall Shear ◽  
Small Aneurysms

scholarly journals Wall shear stress distribution in a model canine artery during steady flow.

1977 ◽  
Vol 41 (3) ◽  
pp. 391-399 ◽  
Author(s):  
R J Lutz ◽  
J N Cannon ◽  
K B Bischoff ◽  
R L Dedrick ◽  
R K Stiles ◽  
...  
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Wall Shear Stress ◽  
Steady Flow ◽  
Shear Stress Distribution ◽  
Wall Shear Stress Distribution ◽  
Wall Shear
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