Study of periodic 2-D eddies in compound open channels

In compound open channels, a shear instabilitiy generates periodic 2-D eddies at the junction between the main channel and the flood plains, so that a pair of vortex streets are formed at the both junctions. Velocity distribution in the channel is determined by the interaction between those two vortex streets. The period of the vortex is derived from a linear stability analysis. The experimental data support the results of the analysis. It is found from the experiments that the interaction between the vortex streets is emphasized when they are arranged in the stable order of the Karman vortex.