Boundary Shear in Rectangular Ducts and Channels

Abstract

The development of the equation for the lateral distribution of boundary shear starts from a simplified streamwise vorticity equation which includes only the secondary Reynolds stress terms. Transverse anisotropy is modeled using a universal function. The effect of secondary flow on the boundary shear is incorporated into the model by applying the momentum transfer model. In the light of these analyses, an empirical equation is put forward to describe the lateral boundary shear distribution. The measured data of boundary shear in square ducts are used to quantify some empirical coefficients. The model is then applied to the corner region of rectangular ducts and open channels. With those simplifications and approximations applied to the streamwise vorticity equation, the predictions are found to be good.