Moving Spatial Turbulence Model for High-Fidelity Rotorcraft Maneuvering Simulation

Abstract

A moving spatial turbulence model is developed for rotorcraft maneuvering simulation under different flight conditions. The recursive algorithms are adopted to model its distributed longitudinal turbulence components, which are correlated with the lateral and vertical axes to form a local spatial turbulence field. The flow field is constrained around the rotorcraft by following its movement, and the corresponding turbulence components are updated at a constant spatial interval. The statistical properties along the longitudinal, lateral, and vertical directions have been validated against the von Kármán theory. A synthetic simulation environment consisting of a flight dynamics model and a pilot model is constructed to demonstrate the effectiveness of the turbulence model. Its performance is validated by comparing the power spectral densities of both rotorcraft responses and pilot controls in turbulence against flight test data. The piloted simulation results on an Approach-to-Hovering task show that the handling qualities ratings are susceptive to the level of turbulence and significantly increase when performing aggressive controls. The simulation also accurately predicts the expected effect of varied aircraft speed, wind speed, turbulence intensity, and stability augmentation system on piloted handling qualities rating for rotorcraft flight in turbulence.