Simulation of Step Input in Collective Pitch for Hovering Rotor

Advanced CFD tools are nowadays used routinely for analysis and design of rotorcraft. Computations for flows around rotors in trim are also common place and slowly the research community is shifting towards simulations of rotorcraft during maneuvering flight. One of the impediments of this effort is the lack of detailed data for validation, evaluation and thorough assessment of CFD methods when it comes to rotors with time-varying inputs. This paper presents a first effort to validate CFD tools for step-inputs in rotor control angles and presents both novel simulations, and un-published experimental data. The results show that there is always a lag involved between the wake and loads response and the operation of low-thrust rotors with dynamic wakes and collective input is a challenging task for modern CFD. The results used in this work originate from a study carried out at the Nanjing University of Aeronautics and Astronautics in China and represent a unique set of great value to the research community. The agreement with simulation results further contributes to the value of the test data.