Boundary Shear Stress in Smooth Trapezoidal Open Channel Flows

AbstractSemianalytical equations were derived to evaluate the mean boundary shear stress in smooth trapezoidal open channels using conformal mapping techniques. This process tends to a complicated function that should be simplified based on numerical integration. Also, based on a mathematical analysis, an approach that divides the flow area into subsections corresponding to the channel bed and sidewalls is presented. In particular, the hydraulic aspects of the best hydraulic trapezoidal sections were characterized to estimate the boundary shear stress distribution based on the exact form of the interface between adjacent subsections. To validate this approach, the analytical results were compared with the results of model experimentation performed in the present study. The analytical results agree well with the experimental measurements and the results of former investigations.

[1]  Shu‐Qing Yang,et al.  Mechanism of energy transportation and turbulent flow in a 3D channel , 1997 .

[2]  Shu-Qing Yang,et al.  Interactions of boundary shear stress, secondary currents and velocity , 2005 .

[3]  Iehisa Nezu,et al.  Turbulence in open-channel flows , 1993 .

[4]  Yee-Chung Jin,et al.  Semianalytical Model for Shear Stress Distribution in Simple and Compound Open Channels , 2008 .

[5]  A. Paquier,et al.  A geometrical method for computing the distribution of boundary shear stress across irregular straight open channels , 1999 .

[6]  H. Morvan,et al.  Numerical Investigation into Secondary Currents and Wall Shear in Trapezoidal Channels , 2011 .

[7]  T. Buffin‐Bélanger.  Leighly, J.B. 1932 Toward a theory of the morphologic significance of turbulence in the flow of water in streams. University of California Publications in Geography 6, 1—22 , 2010 .

[8]  S N Ghosh,et al.  BOUNDARY SHEAR DISTRIBUTION IN OPEN CHANNEL FLOW , 1970 .

[9]  W. Graf.  Hydraulics of Sediment Transport , 1984 .

[10]  Chao-Lin Chiu,et al.  STRUCTURE OF 3-D FLOW IN RECTANGULAR OPEN CHANNELS , 1986 .

[11]  Siow-Yong Lim,et al.  Boundary shear stress distributions in smooth rectangular open channel flows , 1998 .

[12]  Iehisa Nezu,et al.  Three-dimensional turbulent structure in straight open channel flows , 1989 .

[13]  Donald W. Knight,et al.  Boundary Shear in Smooth Rectangular Channels , 1984 .

[14]  S. Tan,et al.  Velocity Distribution and Dip-Phenomenon in Smooth Uniform Open Channel Flows , 2004 .

[15]  P. Julien,et al.  Shear Stress in Smooth Rectangular Open- Channel Flows , 2005 .

[16]  H. A. Einstein,et al.  Formulas for the Transportation of Bed Load , 1942 .

[17]  Siow-Yong Lim,et al.  Boundary shear stress distributions in trapezoidal channels , 2005 .

[18]  Ivar G. Jonsson,et al.  Shear and Velocity Distribution in Shallow Channels , 1964 .