Bottom shear stress in unsteady sewer flow

2006 ◽  
Vol 54 (6-7) ◽  
pp. 93-100 ◽  
Author(s):  
V. Bareš ◽  
J. Jirák ◽  
J. Pollert
Keyword(s):  
Shear Stress ◽  
Turbulent Flow ◽  
Cross Section ◽  
Circular Cross Section ◽  
Distribution Data ◽  
Time Lags ◽  
Bottom Shear Stress ◽  
Flow Conditions ◽  
Turbulent Layer ◽  
Venant Equation

The properties of unsteady open-channel turbulent flow were theoretically and experimentally investigated in a circular cross section channel with fixed sediment deposits. Velocity and turbulence distribution data were obtained using an ultrasonic velocity profiler (UVP). Different uniform flow conditions and triangular-shaped hydrographs were analysed. The hydrograph analysis revealed a dynamic wave behaviour, where the time lags of mean cross section velocity, friction velocity, discharge and flow depth were all evident. The bottom shear stress dynamic behaviour was estimated using four different approaches. Measurements of the velocity distribution in the inner region of the turbulent layer and of the Reynolds stress distribution in the turbulent flow provided the analysed data sets of the bottom shear stress. Furthermore, based on the Saint Venant equation, the bottom shear stress time behaviour was studied using both the kinematic and the dynamic flow principles. The dynamic values of the bottom shear stress were compared with those for the steady flow conditions. It is evident that bottom shear stress varies along the generated flood hydrograph and its variation is the function of the flow unsteadiness. Moreover, the kinematic flow principle is not an adequate type of approximation for presented flow conditions.

Turbulent Flow Over a Facing Step at Several Reynolds Numbers

2011 ◽  
Author(s):  
Jose A. Jimenez-Bernal ◽  
Adan Juarez-Montalvo ◽  
Claudia del C. Gutierrez-Torres ◽  
Juan G. Barbosa Saldan˜a ◽  
Luis F. Rodriguez-Jimenez
Keyword(s):  
Shear Stress ◽  
Velocity Profile ◽  
Turbulent Flow ◽  
Reynolds Numbers ◽  
Spatial Average ◽  
Vortex Center ◽  
Flow Conditions ◽  
Flow Measurements ◽  
Image Velocimetry ◽  
Average Velocity Profile

An experimental study was performed over forward facing step (FFS). It was located within a transparent rectangular acrylic channel (1.4 m in length, 0.1 m in width and 0.02 m in height). The step is 0.01 m in height and 0.1 m in width, and was located 0.7 m downstream (fully developed region); a spanwise aspect ratio, w/h = 10 was used. The experiments were carried out using particle image velocimetry (PIV), which is a non intrusive experimental technique. The experimental water flow conditions include three Reynolds numbers based on the step height, Reh = 1124, 1404 and 1685. These flow conditions correspond to turbulent flow. Measurements were carried out in two zones; zone A begins at x = 8 cm (measured from the step base), and zone B starts at x = 0, y = 0, the visualization region corresponds to an area of 22.76 mm × 16.89 mm. 100 instantaneous velocity fields were obtained for each Reh. A temporal and spatial average was performed to obtain a velocity profile in zone A; likewise, the corresponding turbulence intensity and shear stress distribution were evaluated. The average velocity profile was evaluated for each Reh. Regarding the vortex center location, it was observed that as Reh increases, the y-direction coordinate moves towards bottom of wall channel. For zone B, it was also observed a reduction of the shear stress as Reh increases.

Determining of Shear Modulus for the Samples Circular and Hollow Circular Cross-Section

2016 ◽  
Vol 862 ◽  
pp. 298-304
Author(s):  
Eva Labašová ◽  
Rastislav Ďuriš ◽  
Vladimír Labaš
Keyword(s):  
Shear Stress ◽  
Shear Modulus ◽  
Cross Section ◽  
Theoretical Basis ◽  
Maximum Shear Stress ◽  
Circular Cross Section ◽  
Static Method ◽  
Strength Theory ◽  
Modulus Maximum ◽  
System Quantum

The contribution is focused on estimating the shear modulus of the samples of circular and hollow circular sections by static method. The samples were loaded by simple torsion, individual sections were stressed by shear stress. Theoretical basis are determined by linear elasticity and strength theory and they define the relation between shear modulus, maximum shear stress and relative strains. Relative strains are determined by using measurement apparatus and measurement system Quantum X MX 840.

Stresses in a Reinforced Monocoque Cylinder Under Concentrated Symmetric Transverse Loads

1944 ◽  
Vol 11 (4) ◽  
pp. A235-A239
Author(s):  
N. J. Hoff
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Cross Section ◽  
Maximum Shear Stress ◽  
Circular Cross Section ◽  
Bending Moment ◽  
Normal Stress Distribution ◽  
Transverse Loads ◽  
Conventional Analysis ◽  
Analysis Application

Abstract The stresses in the sheet covering, stringers, and rings of a reinforced monocoque cylinder of circular cross section are calculated for the case of a loading consisting of concentrated symmetric forces applied to the rings in the planes of the rings. The conventional assumptions of a linear normal stress distribution and a corresponding shear-stress distribution in the bent cylinder are replaced by a least-work analysis. Application of the theory to the numerical example of a cantilever monocoque cylinder yields a maximum shear stress in the sheet covering and a maximum bending moment in the ring amounting to 900 per cent and 33 per cent, respectively, of the values obtained by the conventional analysis.

A circular cross-section PDMS microfluidics system for replication of cardiovascular flow conditions

Biomaterials ◽  
2010 ◽  
Vol 31 (13) ◽  
pp. 3459-3464 ◽  
Author(s):  
Lindsey K. Fiddes ◽  
Neta Raz ◽  
Suthan Srigunapalan ◽  
Ethan Tumarkan ◽  
Craig A. Simmons ◽  
...  
Keyword(s):  
Cross Section ◽  
Circular Cross Section ◽  
Flow Conditions ◽  
Cardiovascular Flow

Direct measurement of bottom shear stress under high-velocity flow conditions

2016 ◽  
Vol 50 ◽  
pp. 121-127 ◽  
Author(s):  
Jae Hyeon Park ◽  
Young Do Kim ◽  
Yong Sung Park ◽  
Jae An Jo ◽  
Kimchhun Kang
Keyword(s):  
Shear Stress ◽  
Direct Measurement ◽  
High Velocity ◽  
Bottom Shear Stress ◽  
Flow Conditions ◽  
High Velocity Flow ◽  
Velocity Flow

scholarly journals Flow of a new class of non-Newtonian fluids in tubes of non-circular cross-sections

2019 ◽  
Vol 377 (2144) ◽  
pp. 20180069 ◽  
Author(s):  
Juan P. Gomez-Constante ◽  
Kumbakonam R. Rajagopal
Keyword(s):  
Shear Stress ◽  
Velocity Field ◽  
Cross Section ◽  
Cross Sections ◽  
Applied Mathematics ◽  
Constitutive Relations ◽  
Maximum Shear Stress ◽  
Circular Cross Section ◽  
Secondary Flows ◽  
Shear Stresses

Fluids described by constitutive relations wherein the symmetric part of the velocity gradient is a function of the stress can be used to describe the flows of colloids and suspensions. In this paper, we consider the flow of a fluid obeying such a constitutive relation in a tube of elliptic and other non-circular cross-sections with the view towards determining the velocity field and the stresses that are generated at the boundary of the tube. As tubes are rarely perfectly circular, it is worthwhile to study the structure of the velocity field and the stresses in tubes of non-circular cross-section. After first proving that purely axial flows are possible, that is, there are no secondary flows as in the case of many viscoelastic fluids, we determine the velocity profile and the shear stresses at the boundaries. We find that the maximum shear stress is attained at the co-vertex of the ellipse. In general tubes of non-circular cross-section, the maximum shear stress occurs at the point on the boundary that is closest to the centroid of the cross-section. This article is part of the theme issue ‘Rivlin's legacy in continuum mechanics and applied mathematics’.

scholarly journals Hydraulic resistances experimental and field studies of supply canals and pumping stations structures

2021 ◽  
Vol 264 ◽  
pp. 03075
Author(s):  
Bakhtiyor Uralov ◽  
Marina Li ◽  
Eshmatboy Qalqonov ◽  
Zokhidjon Ishankulov ◽  
Makhfuz Akhmadi ◽  
...  
Keyword(s):  
Turbulent Flow ◽  
Cross Section ◽  
Circular Cross Section ◽  
Pressure Head ◽  
Field Studies ◽  
Calculation Methods ◽  
Flat Bottom ◽  
Plane Parallel ◽  
Pumping Stations ◽  
Large Width

Currently, many authors have studied the uniform axisymmetric pressure head laminar and turbulent movement of water in hydraulic smooth and rough (with uniform roughness) pipes of circular cross-section. The results obtained in the study of a plane-parallel turbulent flow in pressure canals allows here only to outline the structure of the corresponding dependencies and to clarify the simplest case of unpressurized fluid movement, when this movement can also be reduced to plane-parallel or, in other words, to movement in a canal of infinitely large width with a flat bottom. In all other cases, the only way to solve the problem is an experiment. The construction of numerous free-flow watercourses and machine canals of pumping stations requires scientifically based calculation methods.

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