Aerodynamic Investigations of UAV Sensor Turrets -A Combined Wind-tunnel and CFD Approach

摘要

This paper presents unsteady RANS investigations of eight different electro-optical and infrared sensor turret geometries for UAVs. The simulations are validated by comparing them to wind-tunnel drag data of a sensor turret and show good comparability. All turrets feature several sensor surfaces and a dedicated mechanism for 360° field-of-view orientation. The investigations find a variety of vortical structures that surround the turrets, including horseshoe vortices and wake vortices. High levels of flow separation are observed both on sharp sensor surfaces and the edges of the rotational mechanism. This significant flow separation increases drag compared to clean hemisphere-cylinder turrets. The data was used to derive a new and averaged drag coefficient for sensor turrets that can be used in an empirical drag estimation environment. This new drag coefficient is more than 40% higher than compared to clean hemisphere-cylinder turrets.