Optimal placement of an airflow probe at a multirotor UAV for airborne wind measurements

Abstract

For airborne wind measurements at the Wind Energy Research Group at the University of Stuttgart it is planned to use a group of nine multirotor systems to measure environmental quantities. During the design phase of the multirotor system concerns regarding the influence of the aircraft’s rotors on flow measurements have to be addressed. Also the propeller wake of one aircraft may have a great effect on the other aircraft in the group. To deal with this concerns a parameter study has been conducted using a simple two dimensional CFD simulation with an actuator disc model. To verify the simple model a more sophisticated three dimensional simulation with a rotating rotor has been performed for the most relevant operating point of the multirotor. Eventually wind tunnel experiments have been designed to measure the influence in front of the rotors and the wake direction. While the two different models showed reasonable agreement for the investigation of the influence in front of the rotor some differences in the exact development of the wake exist. Nevertheless the extension of the rotor wake could be estimated sufficiently for the planned field measurement campaign and further improvements to the wake estimation have been suggested.