Numerical Analysis of Two-Dimensional Turbulent Flows through an Oscillating Cascade

Abstract

A numerical technique for computation of two-dimensional turbulent flows through an oscillating cascade is presented. To consider the interblade phase angle, a time phase shifted boundary condition is introduced at the periodic boundaries. A finite volume method is used to obtain the spatially discretized governing equations, while the Adams-Bashforth method of second-order accuracy is employed for the time integration. Furthermore, a two-equation model of turbulence is introduced to estimate the turbulence effect. To verify the effectiveness of the present method, computations are carried out for the flow through cascades of flat plate blades (inviscid flow analysis), lens-type blades and compressor blades. The present method gives unsteady periodic flow fields including the periodic aerodynamic force and moment acting on the blade clearly, and the negative damping force is obtained from the computational result of the flat plate cascade flow.