Helicopter Turbulence Modeling with Accurate Spatial Correlations for Handling- Quality Analysis

This paper presents a turbulence model with accurate spatial correlations for helicopter flight simulation and handling-quality analysis. First, digital filters with longitudinal correlations of the von Karman turbulence are developed to generate discrete turbulence velocity components. Turbulence transverse correlations are considered by relating the filters in different positions with spatial correlations of the von Karman theory. Then, the distributions of both the related filters in front of helicopter and their velocity components in the longitudinal direction of airspeed, as well as turbulence models for helicopter aerodynamic surfaces are established. On this basis, a flight dynamics model coupled with the turbulence model is developed and validated against the flight test data. The contribution of each aerodynamic surface to the helicopter handling qualities is analyzed. Finally, the helicopter handling qualities in turbulent atmospheric environment are discussed. The results show that turbulence transverse correlations have important impact on the handling qualities of both the roll and heave motions, while there is a little impact on the handling quality of pitch motion and nearly no impact on that of yaw motion.