Orientation on quantitative IR-thermography in wall-shear stress measurements

LES and URANS Unsteady Boundary Layer Strategies for Pulsating and Oscillating Turbulent Channel Flows Applications

The use of wall functions has been investigated for LES and URANS numerical simulation in pulsating and oscillating channel flow applications. The results show that the wall function approach is accurate in the so-called quasi-steady regime but there are discrepancies with the experimental results in the intermediate frequency range. A special...

Particle image velocimetry for microscale blood flow measurement

The development, the regulation, and the pathology of the circulatory system (e.g. cardiogenesis, thermoregulation, atherosclerosis) are determined by blood flow induced mechanical forces. While this proposition has been confirmed during recent years, the exact mechanisms still remain unclear. This is mainly due to the fact that those forces...

The Micro-Pillar Shear-Stress Sensor MPS3 for Turbulent Flow

Wall-shear stress results from the relative motion of a fluid over a body surface as a consequence of the no-slip condition of the fluid in the vicinity of the wall. To determine the two-dimensional wall-shear stress distribution is of utter importance in theoretical and applied turbulence research. In this article, characteristics of the Micro...

Altered wall shear stresses in embryonic chicken outflow tract due to homocysteine exposure

The embryonic heart is already beating before cardiac morphogenesis is complete. Therefore, the effect of blood flow on cardiogenesis has been subject of many studies. Shear stress, acting on the endocardial cells, has been shown to alter the expression of shear-responsive genes implicated in heart development. The congenital heart defects (CHDs...

Geometrically induced wall shear stress variability in CFD-MRI coupled simulations of blood flow in the thoracic aortas

Aortic aneurysm is associated with aberrant blood flow and wall shear stress (WSS). This can be studied by coupling magnetic resonance imaging (MRI) with computational fluid dynamics (CFD). For patient-specific simulations, extra attention should be given to the variation in segmentation of the MRI data-set and its effect on WSS. We performed...

Hemodynamic Study of a Patient-Specific Intracranial Aneurysm: Comparative Assessment of Tomographic PIV, Stereoscopic PIV, In Vivo MRI and Computational Fluid Dynamics

Introduction: Wall shear stress (WSS) is associated with the growth and rupture of an intracranial aneurysm. To reveal their underlying connections, many image-based computational fluid dynamics (CFD) studies have been conducted. However, the methodological validations using both in vivo medical imaging and in vitro optical flow measurements...

The Correlation Between Wall Shear Stress and Plaque Composition in Advanced Human Carotid Atherosclerosis

The role of wall shear stress (WSS) in atherosclerotic plaque development is evident, but the relation between WSS and plaque composition in advanced atherosclerosis, potentially resulting in plaque destabilization, is a topic of discussion. Using our previously developed image registration pipeline, we investigated the relation between two...

Aortic valve neocuspidization and bioprosthetic valves: Evaluating turbulence haemodynamics

Aortic valve disease is often treated with bioprosthetic valves. An alternative treatment is aortic valve neocuspidization which is a relatively new reparative procedure whereby the three aortic cusps are replaced with patient pericardium or bovine tissues. Recent research indicates that aortic blood flow is disturbed, and turbulence effects...