Body-force effect of friction on quasi-two-dimensional turbulent flows in shallow waters

Friction is considered as a body force with a stabilizing effect on the large-scale two-dimensional turbulent motions in shallow open-channel flows. To maintain a turbulent motion, the turbulent energy production by the transverse shear must be greater than the negative work done against the body force of the friction. Numerical calculations were conducted of the shallow turbulent flows, in the form of the starting jets, for several depths using a two-length-scale turbulence model developed to study the body-force effect. The results of the calculations are compared with a recent experimental observations of the friction effect on the starting jets of small depths.