Aerodynamic characteristics of a thin airfoil cascade in an ideal incompressible flow with separation from the leading edges

A new method of solving the problem of separation flow past a cascade of thin airfoils is proposed. The method is based on the model of separated flow past a single airfoil in which vortex wakes shed from the airfoil edges are modeled by vortex layers with time-averaged intensities. Under the assumption of a small deviation of the freestream angle α from the “impactless entry” angle α 0 the singular integral equation governing the flow kinematics is closed by a dynamic equation. It is shown that the separation effect on the time-averaged aerodynamic characteristics of the cascade is associated with the total pressure loss due to the flow energy expenditure on the vortex wake formation. The aerodynamic characteristics of the cascade calculated with and without account for flow separation differ by the second-order quantity ɛ = α − α 0.