Unsteady Flows Through Cascades : Sinusoidal gusts having different phase for each blade

Abstract

An analytical method is given for the determination of the lift fluctuation on flat plate airfoils in cascade due to transverse and chordwise gusts. The acceleration potential method is used in combination with conformal mapping method. In order to take account of the phase difference of the gusts between adjacent blades, a new mapping function is introduced. The blades are mapped to several unit circles on which the acceleration potential is given to satisfy the boundary conditions. Unsteady lift forces are given for three different stagger angles, five different pitches of the cascades and three different phase differences. The phase difference has the effect to make the lift forces greater than that for the case of the same phase, and this tendency is remarkable when the reduced frequency of the gust is small.