Dynamic stall model optimization with CFD and assessment with comprehensive approach for improved blade design

Abstract

An enhancement for comprehensive modelling of rotor in forward flight is proposed to enable inclusion of dynamic stall and study characteristic effects on rotor loads and performance in design phase. The characterization of dynamic stall behavior of the selected airfoil on the design is performed with validated CFD analyses. Parameter optimization is performed for the dynamic stall and unsteady aerodynamics model in CAMRAD II, comprehensive analysis tool, to attain maximum similarity with CFD based predictions. Optimized dynamic stall model is then utilized to study rotor loads at dynamic stall dominated flight condition. Using the improved analysis framework with optimized dynamic stall model, the effect of anhedral tip shape on blade loads and stall onset characteristics is studied. It is observed that, anhedral modification to a blade tip combined with dynamic stall phenomena, worsens rotor torsional loads. On the other hand, application of an up-wash twist at tip anhedral region, improves the degraded load characteristics. The aim of this study is practice estimation of dynamics stall characteristics of an airfoil of interest with CFD, optimize dynamic stall model in accordance and investigate effect on rotor loads in the presence of anhedral.