ABSTRACT
The previous chapters concentrated on the two-dimensional (2-D) flow structure that is fundamental and essential to an understanding of open-channel turbulence. However, real flows in open-channels and rivers are often too complex to be represented as 2-D flows. Thus, the turbulence models developed for 2-D flows may not give useful results for three-dimensional (3-D) flows, not even for simple boundary conditions. Clarification of secondary currents is essential for an understanding of 3-D turbulent flow structures, and then 3-D turbulence models must be developed on the basis of knowledge about secondary currents in turbulent shear flows.
