scholarly journals Visualization of Surface Flow over a Blade of Rotating Machinery by Oil-Film Technique and Measurement of Shear Stress Distribution by Image Analysis.

2000 ◽  
Vol 20 (79) ◽  
pp. 350-355 ◽  
Author(s):  
Atsushi NASHIMOTO ◽  
Nobuyuki FUJISAWA ◽  
Eiichi KIMURA ◽  
Tsuneo AKUTO
Keyword(s):  
Shear Stress ◽  
Image Analysis ◽  
Stress Distribution ◽  
Rotating Machinery ◽  
Surface Flow ◽  
Shear Stress Distribution ◽  
Oil Film

scholarly journals Visualization and image analysis of shear stress distribution over a fan blade

1999 ◽  
Vol 19 (Supplement2) ◽  
pp. 137-140
Author(s):  
Atsushi Nashimoto ◽  
Nobuyiki Fujisawa ◽  
Eiichi Kimura ◽  
Tsuneo Akuto
Keyword(s):  
Shear Stress ◽  
Image Analysis ◽  
Stress Distribution ◽  
Shear Stress Distribution ◽  
Fan Blade

Three-Dimensional Scouring Analysis for Open Channel Pressure Flow Scour Under Flooded Bridge Decks

2011 ◽  
Author(s):  
Bhaskar Rao Tulimilli ◽  
Steven A. Lottes ◽  
Pradip Majumdar ◽  
Milivoje Kostic
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Bridge Decks ◽  
Three Dimensional ◽  
Critical Shear Stress ◽  
Surface Flow ◽  
Shear Stress Distribution ◽  
Physical Models ◽  
Computational Domain ◽  
Shape And Size

A three-dimensional stream bed scour modeling methodology was developed using well-benchmarked commercial Computational Fluid Dynamics (CFD) software to compute the bed shear stress distribution used to calculate bed displacements and to re-mesh the computational domain as the bed is displaced. This study extends a previously developed two-dimensional iterative scouring procedure to predict the final shape and size of the scour-hole under pressure-scour flow conditions for flooded bridge decks using commercial CFD software. The current approach uses single phase flow models with an assumed flat water surface using a symmetric slip top boundary to simulate a free-surface flow condition, quasi-steady simulation to obtain the bed shear, and a moving boundary formulation based on an empirical correlation for critical shear stress to iteratively deform the bed under supercritical shear conditions until an equilibrium scour condition is obtained. The model solves the flow field using Reynolds Averaged Navier-Stokes (RANS) equations and the high Reynolds number k–epsilon turbulence model using the commercial CFD software STAR-CD. A Bash script was developed to use a Python script to compute bed displacements from the computed shear stress distribution and generate a STAR-CD processor command file to displace the bed followed by a step using the STAR-CCM+ software to remesh the domain as the bed is displaced and bed shear distribution is recomputed in an iterative procedure until the equilibrium bed contour is reached. Simulations were performed for different inundation ratios and for mean sand diameters of 1 mm and 2 mm. The model agrees reasonably well with limited experimental data for equilibrium scour shape and size with fully submerged cases compared to the cases where the bridge deck is partially submerged. This developed three-dimensional CFD scour computation procedure provides a basis for testing of additional scour related physical models while also providing an evaluation tool that can be used immediately by engineers engaged in scour risk analysis and assessment.

Bed Shear Stress of a Flowing Meandering Fluid-Structure Interaction

2005 ◽  
Author(s):  
L. Yilmaz
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Stress Distribution ◽  
Fluid Velocity ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Shear Stress Distribution ◽  
The Stability ◽  
Meander Evolution ◽  
Hot Film

An analytical model is developed for free-surface flow over an erodible bed and is used to investigate the stability of the fluid-bed interface and the characteristics of the bed features by measuring the shear stress distribution with hot-film sensors. The model is based on the potential flow over a two-dimensional, moving, wavy bed with a sinusoidal profile of varying amplitude, and a sediment transport relation in which the transported rate is proportional to the power of the fluid velocity at the level of the meandering bed. Consideration is given to the factors involved in determining the shear stress distribution at the flow boundary layer. The experimental results are presented in two parts. Experimental observations of meander evolution described qualitatively. The most important parameter is the shear stress distribution, because of the inhomogeneous distribution of boundary layer meander features. At the wavy boundary layer, the shear stress distribution, measured with WTG-50 hot-film-anemometer is given graphically and theoretically.

scholarly journals Assessing Machine Learning versus a Mathematical Model to Estimate the Transverse Shear Stress Distribution in a Rectangular Channel

Mathematics ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 596
Author(s):  
Babak Lashkar-Ara ◽  
Niloofar Kalantari ◽  
Zohreh Sheikh Khozani ◽  
Amir Mosavi
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Fuzzy Inference ◽  
Rectangular Channel ◽  
Tsallis Entropy ◽  
Shear Stress Distribution ◽  
Data Series ◽  
Shear Stresses ◽  
Inference System ◽  
Aspect Ratios

One of the most important subjects of hydraulic engineering is the reliable estimation of the transverse distribution in the rectangular channel of bed and wall shear stresses. This study makes use of the Tsallis entropy, genetic programming (GP) and adaptive neuro-fuzzy inference system (ANFIS) methods to assess the shear stress distribution (SSD) in the rectangular channel. To evaluate the results of the Tsallis entropy, GP and ANFIS models, laboratory observations were used in which shear stress was measured using an optimized Preston tube. This is then used to measure the SSD in various aspect ratios in the rectangular channel. To investigate the shear stress percentage, 10 data series with a total of 112 different data for were used. The results of the sensitivity analysis show that the most influential parameter for the SSD in smooth rectangular channel is the dimensionless parameter B/H, Where the transverse coordinate is B, and the flow depth is H. With the parameters (b/B), (B/H) for the bed and (z/H), (B/H) for the wall as inputs, the modeling of the GP was better than the other one. Based on the analysis, it can be concluded that the use of GP and ANFIS algorithms is more effective in estimating shear stress in smooth rectangular channels than the Tsallis entropy-based equations.

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
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