Aerodynamic interactions between the steady cascade loading and inflow gust vorticity. Vorticity effect in turbine rotor cascade.

Abstract

The aim of the present paper is to show that the aerodynamic interactions between the gust vorticity and steady loading of a rotor cascade play a significantly important role, particularly in a turbine cascade by regarding the viscous wake rows shed by upstream nozzle cascade as inviscid sinusoidal gust. Through some notable deformations of equi-vorticity lines within rotor passage shearing of equi-vorticity lines over the rotor surface and its downstream, unsteady secondary flow by pair vortics etc are shown to be well explained. Further significant influences of the vorticity on the surface pressure distributions, the tangential and axial fluid forces and moment are clarified by numerical examples in the circumferential velocity and inflow gust phase.