The Cascade Subjected to Inlet Distortions

Abstract

SummaryThis paper presents a method for evaluating the effects of shear flow on the performance of a two-dimensional cascade in an incompressible fluid. The method of distributing the singularities along the chord is modified to meet the requirement that the sum of the distorted and perturbed velocities should produce a flow around the aerofoil; therefore an actuator-disc or flat-plate type approximation is not used. Attention is confined to a single row of arbitrary aerofoils subjected to pure harmonic distortions, no attempt being made to include time-dependent terms. Hence it is probable that this paper offers the first stage of a time-independent solution for assessing the effects of upstream struts or blade rows. The agreement between this method and the exact solution for an isolated flat-plate aerofoil is fairly good.Numerical examples are presented and discussed with reference to the changes of lift, deviation angle and surface velocity which distortion over the cascade would produce. It is found, for the limited number of examples calculated, that a positively-staggered cascade readily responds to the variation of geometrical parameters chosen.