Аннотация:A review of experimental and numerical studies on the boundary layer of water and air flows withdecreasing velocity along the flow direction is presented. It has been experimentally established thatan adverse pressure gradient in water and air flows leads to periodic deceleration of the boundarylayer in plane-parallel flow. During deceleration, the vertical velocity profile deforms, creating a localminimum located between two inflection points above the viscous layer. It is shown that within thethin layer containing the upper inflection point, the plane-parallel flow is unstable, as confirmed byexperiments — within this layer, the formation of a cylindrical vortex is observed at a critical valueof the adverse pressure gradient at the end of the deceleration cycle. The parameters of the vortexchain have been obtained, and the deformation of vortices in a flow with velocity shear, as well asthe impact of vortices on the underlying surface, has been investigated. Physical mechanisms havebeen identified for the formation of ridges on an erodible surface under water flow, the generationof wind waves on an initially flat water surface, and the formation of a wall of water and sedimentin flows during dam breaks
