scholarly journals DPTV-based analysis of the flow-structure/wall-shear interplay in open wet clutches

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Robin Leister ◽  
Jochen Kriegseis
Keyword(s):  
Adverse Effect ◽  
Shear Stress ◽  
Fluid Flow ◽  
Energy Consumption ◽  
Wall Shear Stress ◽  
Automotive Industry ◽  
Lower Energy ◽  
Drag Torque ◽  
Clear Identification ◽  
Wall Shear

The trend to lower energy consumption in the automotive industry still offers potential in various fields of application. One powerful saving strategy is described by the idling behavior of wet clutches, where the speed difference between drive and output, and the cooling oil in combination with a sub-millimeter spacing leads to significant amounts of wall shear stress (WSS) and accordingly drag torque. Minimization of this adverse effect has been found to be possible by means of grooved clutch-disk geometries, which have been demonstrated to correlate with the drag torque (see e.g. Neupert et al., 2018). The main interplay between torque and fluid flow in open wet clutches has been analyzed by Leister et al. (2020) in a dimensionless way. Today, a detailed investigation of a clutch flow, however, is missing for a larger variety of groove patterns and the cause-effect relations remain yet to be fully understood. Especially, the clear identification of the so-called foot print of a particular groove geometry in the flow field and corresponding WSS – thus drag-torque predictions – still requires further research efforts.

The influence of magnetic field on wall shear stress in power law fluid flow of blood

2021 ◽  
Author(s):  
Amira Husni Talib ◽  
Ilyani Abdullah ◽  
Nik Nabilah Nik Mohd Naser
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Fluid Flow ◽  
Wall Shear Stress ◽  
Power Law ◽  
Power Law Fluid ◽  
Wall Shear

scholarly journals FLUID FLOW AND WALL SHEAR STRESS PROFILES IN MODEL BRANCH OF ABDOMINAL AORTA

Biomechanisms ◽  
1992 ◽  
Vol 11 (0) ◽  
pp. 99-109 ◽  
Author(s):  
Takashi HIROSE ◽  
Akio TANABE ◽  
Kazuo TANISHITA
Keyword(s):  
Shear Stress ◽  
Fluid Flow ◽  
Wall Shear Stress ◽  
Abdominal Aorta ◽  
Stress Profiles ◽  
Wall Shear

scholarly journals Lymphatic endothelial cell calcium pulses are sensitive to spatial gradients in wall shear stress

2019 ◽  
Vol 30 (7) ◽  
pp. 923-931
Author(s):  
Vinay N. Surya ◽  
Eleftheria Michalaki ◽  
Gerald G. Fuller ◽  
Alexander R. Dunn
Keyword(s):  
Shear Stress ◽  
Fluid Flow ◽  
Wall Shear Stress ◽  
Cell Types ◽  
General Question ◽  
Pulse Dynamics ◽  
Spatial Gradients ◽  
Wall Shear ◽  
Valve Formation

Cytosolic calcium (Ca2+) is a ubiquitous second messenger that influences numerous aspects of cellular function. In many cell types, cytosolic Ca2+ concentrations are characterized by periodic pulses, whose dynamics can influence downstream signal transduction. Here, we examine the general question of how cells use Ca2+ pulses to encode input stimuli in the context of the response of lymphatic endothelial cells (LECs) to fluid flow. Previous work shows that fluid flow regulates Ca2+ dynamics in LECs and that Ca2+-dependent signaling plays a key role in regulating lymphatic valve formation during embryonic development. However, how fluid flow might influence the Ca2+ pulse dynamics of individual LECs has remained, to our knowledge, little explored. We used live-cell imaging to characterize Ca2+ pulse dynamics in LECs exposed to fluid flow in an in vitro flow device that generates spatial gradients in wall shear stress (WSS), such as are found at sites of valve formation. We found that the frequency of Ca2+ pulses was sensitive to the magnitude of WSS, while the duration of individual Ca2+ pulses increased in the presence of spatial gradients in WSS. These observations provide an example of how cells can separately modulate Ca2+ pulse frequency and duration to encode distinct forms of information, a phenomenon that could extend to other cell types.

Study of the Effect of Spacer Orientation and Shape in Membrane Feed Channel using CFD Modelling

2014 ◽  
Vol 70 (2) ◽  
Author(s):  
H. C. Teoh ◽  
S. O. Lai
Keyword(s):  
Shear Stress ◽  
Energy Consumption ◽  
Pressure Drop ◽  
Wall Shear Stress ◽  
Flow Direction ◽  
Cfd Modelling ◽  
Power Number ◽  
Lower Power ◽  
Velocity Magnitude ◽  
Wall Shear

Computational fluids dynamics (CFD) modelling has been carried out for a spacer-filled membrane channel using ANSYS FLUENT 14.0. The effect of spacer angles relative to the feed flow direction and different spacer shape combinations on velocity magnitude, wall shear stress, pressure drop and power number were investigated. From the results, spacer angle of 63.565° is the best orientation as it can generate the highest shear stress and reasonably lower power number compared to other spacer angles. Although the combinations of spacer shape did not significantly improve the average wall shear stress, it helped in reducing the pressure drop of the channel. The combination of triangular and circular spacers provided lower Power number, and hence lower energy consumption was required compared to pure triangular spacer. The current results indicated that a combination of triangular and circular spacers can be employed to offer better saving in energy consumption.

Induction of NO and prostaglandin E2 in osteoblasts by wall-shear stress but not mechanical strain

1997 ◽  
Vol 273 (4) ◽  
pp. E751-E758 ◽  
Author(s):  
R. Smalt ◽  
F. T. Mitchell ◽  
R. L. Howard ◽  
T. J. Chambers
Keyword(s):  
Shear Stress ◽  
Fluid Flow ◽  
Wall Shear Stress ◽  
Bone Cells ◽  
Mechanical Strain ◽  
Osteoblastic Cells ◽  
Long Bone ◽  
Shear Stresses ◽  
No Production ◽  
Wall Shear

The nature of the stimulus sensed by bone cells during mechanical usage has not yet been determined. Because nitric oxide (NO) and prostaglandin (PG) production appear to be essential early responses to mechanical stimulation in vivo, we used their production to compare the responsiveness of bone cells to strain and fluid flow in vitro. Cells were incubated on polystyrene film and subjected to unidirectional linear strains in the range 500–5,000 microstrain (με). We found no increase in NO or PGE2 production after loading of rat calvarial or long bone cells, MC3T3-E1, UMR-106–01, or ROS 17/2.8 cells. In contrast, exposure of osteoblastic cells to increased fluid flow induced both PGE2 and NO production. Production was rapidly induced by wall-shear stresses of 148 dyn/cm2 and was observed in all the osteoblastic populations used but not in rat skin fibroblasts. Fluid flow appeared to act through an increase in wall-shear stress. These data suggest that mechanical loading of bone is sensed by osteoblastic cells through fluid flow-mediated wall-shear stress rather than by mechanical strain.

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