Torsional Flutter in Stalled Cascade

Abstract

Applying free streamline theory and singularity method, a theoretical study is developed for the torsional flutter problem in fully stalled cascade. Aerodynamic moment acting on a vibrating blade is calculated for some cascade conditions. Computational results show that critical reduced frequency is much higher in the case of stalled cascade than unstalled cascade and affected by the position of pitching center. Experiments were carried out using a water tunnel with a linear cascade, and the unsteady moment acting on the vibrating blade was measured. Computational and experimental results show fairly good agreement.