On the relationship between the work of adhesion and the critical shear stress for the onset of flow instabilities

2005 ◽  
Vol 45 (5) ◽  
pp. 705-715 ◽  
Author(s):  
H.J. Larrazabal ◽  
A.N. Hrymak ◽  
J. Vlachopoulos
Keyword(s):  
Shear Stress ◽  
Critical Shear Stress ◽  
Flow Instabilities ◽  
Work Of Adhesion ◽  
The Relationship

scholarly journals Experimental study on incipient condition of fluidized bed sediment in oscillatory

2019 ◽  
Vol 81 ◽  
pp. 01014
Author(s):  
Rui Wang ◽  
Guoliang Yu
Keyword(s):  
Shear Stress ◽  
Yield Stress ◽  
Fluidized Bed ◽  
Oscillatory Flow ◽  
Critical Shear Stress ◽  
Cohesive Sediments ◽  
Bed Sediment ◽  
The Relationship ◽  
Experimental Runs ◽  
Water Contents

In this paper, the incipient condition of the fluidized bed sediment with different sizes and water contents were experimentally studied in an os- cillatory tunnel made of acrylic boards. One-hundred experimental runs were performed with sediment samples by varying the yield stress to determine the relationship between the critical condition of incipient motion and the rheolog- ical properties of the cohesive sediments. Experimental results showed that the yield stress of the bed sediment decreased as the fluidization level increased. When the yield stress is no longer changed, the bed sediment was considered completely fluidized. In oscillatory flow, the critical shear stress decreases with the increase of fluidization level. When the bed sediment reaches the full flu- idization state, the critical shear stress of the bed sediment at the bottom re- mained constant. For cohesive sediments, in the case that particle size and bulk density were known, the relationship between the yield stress and the critical shear stress was analyzed, and the incipient condition of the cohesive sediment under oscillatory flow action was determined.

scholarly journals ANALISIS ANGKUTAN SEDIMEN DASAR (BED LOAD) PADA SALURAN IRIGASI MATARAM YOGYAKARTA

Teknisia ◽  
2021 ◽  
Vol XXVI (1) ◽  
Author(s):  
Anggi Hermawan ◽  
◽  
Erwin Afiato ◽  
Keyword(s):  
Shear Stress ◽  
Sediment Transport ◽  
Froude Number ◽  
Critical Shear Stress ◽  
Bed Load ◽  
Cross Sectional ◽  
Logarithmic Curve ◽  
Agricultural Areas ◽  
The Relationship ◽  
Downstream Area

In the last decade, the problem that has occurred in the Yogyakarta Mataram irrigation channel is the occurrence of sedimentation in the channel. This has an impact on reducing the cross-sectional discharge capacity of the canal and resulting in the supply of irrigation discharge to agricultural areas to be not optimal, so that agricultural productivity in the Mataram Irrigation Area will also not be optimal. The sediment transport (bed load) that occurs in an open channel can be approached using the empirical equation, including the Einstein, Meyer - Peter Muller and Frijlink equations. Sediment transport events that occur in the channel are stated based on the magnitude of the flow shear stress which exceeds the critical shear stress of the sediment particles. The quantity of sediment transport in the channel is stated on the logarithmic curve of the relationship between the froude number (fr) to the sediment transports (qb). The Curve explains that the increase in the froude number (fr) that occurs on each section of the channel will be directly proportional to the increase in the quantity of transport sediment (qb). The largest sediment transport occurred at the site of the Gambang and Nambongan channel section with a prediction of sediment transport of 3.57 m3/day and 3.67 m3/day, respectively. Thus, the potential for sediment transport that will settle in the downstream area is 3.67 m3/day.

Modifications to the design procedure for grit chambers

1987 ◽  
Vol 14 (2) ◽  
pp. 216-220 ◽  
Author(s):  
Sunil K. Agrawal ◽  
Jatinder K. Bewtra
Keyword(s):  
Shear Stress ◽  
Key Words ◽  
Critical Shear Stress ◽  
Design Procedure ◽  
Bed Shear Stress ◽  
Flow Conditions ◽  
Mean Velocity ◽  
Particle Characteristics ◽  
The Relationship

A modified approach to the design of grit chambers has been suggested in this paper. This approach is based on the concept of critical shear stress at the bed rather than mean velocity as used by T. R. Camp. It is recognized that the relationship between critical bed shear stress and mean velocity in a channel is not constant, as assumed by Camp, but varies according to the flow conditions. Critical bed shear stress values, obtained in the laboratory for different particle characteristics, are given in this paper. The proposed method should provide a more rational and a better design procedure for grit chambers. Key words: grit chambers, scouring, bed shear stress, initiation of motion.

Field evidence of resuspension in a mine tailings pond

2001 ◽  
Vol 38 (4) ◽  
pp. 796-808 ◽  
Author(s):  
Celestina Adu-Wusu ◽  
Ernest K Yanful ◽  
Mohammed H Mian
Keyword(s):  
Shear Stress ◽  
Mine Tailings ◽  
Critical Shear Stress ◽  
Field Measurements ◽  
Shear Stresses ◽  
Wind Speeds ◽  
Tailings Pond ◽  
Field Evidence ◽  
Water Cover ◽  
Solubility Of Oxygen

Flooding of tailings under shallow water covers is an effective method of decommissioning potentially acid generating mine tailings. The low diffusivity and solubility of oxygen in water are attractive features of this technology. However, wind-induced waves can resuspend flooded tailings and expose them to greater contact with dissolved oxygen, thereby increasing the potential for oxidation and acid generation. Field measurements of wind activity and waves under different water cover depths and associated resuspension for a mine tailings pond in Ontario are presented and discussed. The results show that wind speeds greater than 8 m/s above water covers that are shallower than 1 m create waves of height greater than 10 cm and bottom shear stresses greater than 0.2 Pa. Under these conditions the critical shear stress of the mine tailings was exceeded, resulting in erosion and subsequent resuspension.Key words: mine tailings, water cover, wind-induced waves, resuspension, wind speed, shear stress.

ESTIMATION OF CRITICAL SHEAR STRESS OF SEDIMENT USING ROTATIONAL VISCOMETER

2021 ◽  
Vol 77 (2) ◽  
pp. I_1039-I_1044
Author(s):  
Shinya NAKASHITA ◽  
Kyeongmin KIM ◽  
Yuki IMAMURA ◽  
Tadashi HIBINO
Keyword(s):  
Shear Stress ◽  
Critical Shear Stress ◽  
Rotational Viscometer

Experimental Study on Critical Shear Stress of Cohesive Soils and Soil Mixtures

2021 ◽  
Vol 64 (2) ◽  
pp. 587-600
Author(s):  
Xiaojing Gao ◽  
Qiusheng Wang ◽  
Chongbang Xu ◽  
Ruilin Su
Keyword(s):  
Experimental Data ◽  
Shear Stress ◽  
Critical Shear Stress ◽  
Cohesive Soil ◽  
Future Research ◽  
Cohesive Soils ◽  
List Type ◽  
Soil Mixture ◽  
Linear Relationships ◽  
Soil Mixtures

HighlightsErosion tests were performed to study the critical shear stress of cohesive soils and soil mixtures.Linear relationships were observed between critical shear stress and cohesion of cohesive soils.Mixture critical shear stress relates to noncohesive particle size and cohesive soil erodibility.A formula for calculating the critical shear stress of soil mixtures is proposed and verified.Abstract. The incipient motion of soil is an important engineering property that impacts reservoir sedimentation, stable channel design, river bed degradation, and dam breach. Due to numerous factors influencing the erodibility parameters, the study of critical shear stress (tc) of cohesive soils and soil mixtures is still far from mature. In this study, erosion experiments were conducted to investigate the influence of soil properties on the tc of remolded cohesive soils and cohesive and noncohesive soil mixtures with mud contents varying from 0% to 100% using an erosion function apparatus (EFA). For cohesive soils, direct linear relationships were observed between tc and cohesion (c). The critical shear stress for soil mixture (tcm) erosion increased monotonically with an increase in mud content (pm). The median diameter of noncohesive soil (Ds), the void ratio (e), and the organic content of cohesive soil also influenced tcm. A formula for calculating tcm considering the effect of pm and the tc of noncohesive soil and pure mud was developed. The proposed formula was validated using experimental data from the present and previous research, and it can reproduce the variation of tcm for reconstituted soil mixtures. To use the proposed formula to predict the tcm for artificial engineering problems, experimental erosion tests should be performed. Future research should further test the proposed formula based on additional experimental data. Keywords: Cohesive and noncohesive soil mixture, Critical shear stress, Erodibility, Mud content, Soil property.

Sign in / Sign up

Export Citation Format

Share Document