Numerical Study of Effect of Leading Edge Configurations on Cascade Characteristics of Thin Arc Airfoil.

Abstract

Steady and unsteady cascade flow characteristics of thin arc airfoil is numerically investigated. In comparison with thick airfoil, flow field around thin airfoil is quite sensitive to its leading edge configuration. In this study, new type of leading edge configuration is proposed, and two types of thin arc airfoil are calculated to investigate the improvement by our design. We tested thin arc airfoil (TA) and front-thicken airfoil (FA) having thickened leading edge. Since fluctuation of drag coefficient becomes smaller in FA cascade, aerodynamic characteristic of FA cascade is robust with respect to the change in attack angle. Although existence of periodic separation bubble are observed in both cascades in high attack angle cases, the hysteretic excursion on a map of reattachment point vs. downstream separation point of suction side surface revealed that thickness of leading edge suppresses the interaction between separaion bubble and wake from downstream separation point.