Аннотация:Numerical and physical simulation of the laminar and turbulent flows in a channel of rectangular
cross-section with a circular cavity in one wall has made possible a detailed analysis of the three-dimensional
structures in the separation zone. The differences between the laminar and turbulent flow regimes are noted. A
common feature of the three-dimensional separation flows is the existence of singular points on the surfaces
washed by the fluid; from the vicinities of these points the fluid flows out in the form of swirled jets into the
space above these surfaces. The quasi-two-dimensional nature of the flow in the cell is practically undistorted
by the above-mentioned three-dimensional effects. The latter are determined by the transverse component of the
velocity (i.e., its projection on the x, z plane), which in this case does not exceed 9% of the velocity in the
channel. The intensity of the flow in the large-scale vortex depends only slightly on the presence of lateral walls. A maximum of the return flow velocity is reached in the base region of the cell and in the turbulent regime
amounts to 40% of the channel flow velocity.