Analysis of helicopter handling quality in turbulence with recursive von Kármán model

Abstract

A recursive von Kármán turbulence model is developed and integrated into the current distributed turbulence model for helicopter flight simulation and handling quality analysis in atmospheric turbulence. First, high-order filters are developed with rational expressions to approximate the von Kármán spectra. Recursive algorithms for modeling the von Kármán turbulence are derived by discretizing the filters with the Tustin transform. Then, the recursive von Kármán turbulence model is used to replace the Dryden model in the current distributed turbulence model for helicopter flight simulation in atmospheric turbulence. The results show that the spectra of the recursive von Kármánturbulence have an excellent agreement with the theoretical von Kármánspectra, and they are valid over a normalized frequency range up to 400 rad, which is suitable for helicopter handling quality analysis in atmospheric turbulence with low flight speed and large turbulence scale lengths. The present turbulence model significantly extends the capability of helicopter handling quality analysis to the higher-altitude and lower-velocity flight conditions compared with the current distributed turbulence model.