Efficient CFD approaches for coaxial rotor simulations

The advent of small-scale multicopter aircraft including quad-and octocopter configurations has opened the door to potential cost-effective vertical flight technology. These aircraft are intended to be used in applications such as public transportation, recreational products, commercial vehicles, military technologies, and even extraterrestrial planetary exploration. As the demand for these aircraft continues to rise, analysis capabilities for their design and performance prediction become increasingly useful. Complex problems such as rotor-rotor interactions call for high-fidelity prediction tools, but conventional approaches with these tools have immense computational demand. In this work, two different computational fluid dynamics approaches are implemented using the STAR-CCM+ and RotCFD programs to analyze a coaxial configuration and are compared to conventional (time-accurate) results. The methodology, benchmarking process, and preliminary results indicate that the modeling approaches have potential for future analyses to support engineering design. They reduce the computational cost by more than two orders-of-magnitude over the conventional solution method while still providing a CFD resolved solution, which is within 2% of rotor thrust, power, and figure of merit in hover.