Simplified Propeller Model for the Study of UAV Aerodynamics using CFD method

Unmanned Aerial Vehicle (UAV) has received a lot of consideration in many applications nowadays. Modern UAVs have been designed not only for performance but for efficiency as well. Propeller is an important part for UAV performance. However, the wake from the propeller or propeller induced-flow could interfere with the UAV aerodynamics. For UAV design and aerodynamics analysis, the computational fluid dynamics (CFD) method is a cost-efficient, popular method. But, the full flow simulation of UAV with actual propeller model can be quite complex, time-consuming, and require high computational resource. In this study, a virtual rotor model is deployed in CFD environment in order to computationally-efficiently simulate the airflow generated by UAV propeller. The virtual rotor considers the propeller disk as a surface of pressure difference. The parameters of the virtual rotor are obtained for the propeller approximation model developed in previous work Ill. In this paper, the CFD simulations of wake (airflow velocity) from a commercially-available propeller using its actual propeller (3D-scan) model and the virtual model in a hovering condition are investigated. The CFD simulations using actual propeller model and virtual model show errors of 15-18% and 10-15% from averaged thrust of static test data at the operating RPM, respectively. The comparison results also show an agreement between airflows of actual and virtual models.