Numerical study of the Kelvin-Helmholtz instability resolution in a floodplain channel flow

Models of water flows with different velocities in the river channel are studied. The tangential velocity discontinuity causes development of the so-called Kelvin and Helmholtz instability. The mathematical statement of the problem of studying instability based on the two-dimensional planimetric equations of the turbulent flow hydrodynamics was formulated. When constructing a numerical model, a finite difference scheme of a high spatial resolution is used, providing a possibility of the direct description of large eddies generated in the turbulence field on the line of separation. Analysis of energy transformations in the system “channel-floodplain” is made, the possibility of realization of the antigradient transport, known as negative viscosity phenomenon, is shown.