K. Nadaoka et H. Yagi, SHALLOW-WATER TURBULENCE MODELING AND HORIZONTAL LARGE-EDDY COMPUTATION OF RIVER FLOW, Journal of hydraulic engineering, 124(5), 1998, pp. 493-500
By introducing the concept of ''SDS (subdepth scale) turbulence'' to m
odel three-dimensional (3D) turbulence with length scales less than th
e water depth and treating it explicitly with a proper separate modeli
ng, an SDS-2DH model has been developed to simulate the evolution of h
orizontal large-scale eddies in shallow water. Applying this model to
river flows with transverse shear due to vegetation drag, the horizont
al large-scale (HLS) eddies were found to dominate horizontal momentum
mixing. The bottom friction and vegetation drag, acting as sinks of v
orticity, play the key roles in the development of the horizontal larg
e-scale eddies and in Reynolds stress generation. The SDS-2DH model ca
n directly describe effects of flow geometry, such as vegetation layer
width, on the large-scale eddy development and, hence, predicts turbu
lence-mixing better than the k-epsilon model.