Problems of Flow Separation Detection By Pressure Sensors on a Unmanned Aerial Vehicles with a Propeller

An experimental study of pulsations characteristics of the zone of flow separation arising at a small airplane- type UAV with a pushing two-blade propeller were carried out. The measurements were done in wind tunnel by unsteady pressure sensors and microphones built into the skin of the UAV for the test cases with and without a rotating propeller. A significant effect of the propeller on the level of pulsations was found. An increase of the incoming flow velocity led to a weakening of this effect. Analysis of the spectral data of the disturbances did not reveal a direct relationship between the propeller noise and the unsteady characteristics of the separation zone.