Determination of Friction Factor over a Pool Reach by Double-average Method

Bed-form characteristics have been investigated because of the close relation to hydraulic friction. Pool is one of the most important bed forms in coarse-bed rivers. The form friction factor should be considered in determining many river engineering projects including stable channel design, the scour depth along bank protection and at bridges piers. This study was conducted in the coarse-bed, Saymareh river, in western Iran. Two reaches, with Froude number less than 1.0, were selected to investigate the contribution of the double-average method in determining friction factor, one with pool bed form, range of Reynolds numberfrom 1.325×10

[1]  Atefeh Fazlollahi,et al.  Effect of streamwise pool geometry on shear stresses. , 2014 .

[2]  F. Petit,et al.  The relationship between shear stress and the shaping of the bed of a pebble-loaded river la rulles—Ardenne , 1987 .

[3]  André Robert,et al.  Characteristics of velocity profiles along riffle-pool sequences and estimates of bed shear stress , 1997 .

[4]  Howard H. Chang.  Fluvial Processes in River Engineering , 1988 .

[5]  François Anctil,et al.  Accelerating shear velocity in gravel-bed channels , 2000 .

[6]  Roger H. Shaw,et al.  Double-averaging methodology and its application to turbulent flow in and above vegetation canopies , 2008 .

[7]  Rui M. L. Ferreira,et al.  Parameterization of the logarithmic layer of double-averaged streamwise velocity profiles in gravel-bed river flows , 2008 .

[8]  Keith Richards,et al.  Estimation of flow resistance in gravel‐bedded rivers: A physical explanation of the multiplier of roughness length , 1992 .

[9]  M. Selim Yalin,et al.  Mechanics of sediment transport , 1972 .

[10]  François Petit.  The evaluation of grain shear stress from experiments in a pebble-bedded flume , 2007 .

[11]  Vijay P. Singh,et al.  Estimation of Friction Factor in Open Channels , 2010 .

[12]  Vijay P. Singh,et al.  Determination of Form Friction Factor , 2010 .

[13]  T. Lisle.  A Sorting Mechanism for a Riffle-Pool Sequence , 1979 .

[14]  V. Nikora,et al.  Characteristics of turbulent unidirectional flow over rough beds: Double‐averaging perspective with particular focus on sand dunes and gravel beds , 2006 .

[15]  Vladimir Nikora,et al.  Double-Averaging Concept for Rough-Bed Open-Channel and Overland Flows: Theoretical Background , 2007 .

[16]  H. Schlichting.  Boundary Layer Theory , 1955 .

[17]  Keith Richards,et al.  The influence of microform bed roughness elements on flow and sediment transport in gravel bed rivers: Comment on a paper by marwan A. Hassan and ian reid , 1992 .

[18]  W. N. Melhorn,et al.  Rhythmic spacing and origin of pools and riffles , 1978 .

[19]  Vijay P. Singh,et al.  Effect of Bed Forms and Vegetated Banks on Velocity Distributions and Turbulent Flow Structure , 2011 .

[20]  S. R. McLean,et al.  Spatially averaged flow over a wavy surface , 1977 .

[21]  M. Wolman.  A method of sampling coarse river‐bed material , 1954 .

[22]  A. Roy,et al.  1 min in the life of a river: selecting the optimal record length for the measurement of turbulence in fluvial boundary layers , 2005 .

[23]  André Robert,et al.  Bed configuration and microscale processes in alluvial channels , 1993 .

[24]  André Robert,et al.  Boundary roughness in coarse-grained channels , 1990 .