Abstract
Recently, development of a micro-UAV(Unmanned Aerial Vehicle), which moves in small and complicated 3D spaces freely and is equipped with multitasking sensors, is required for gathering information and resource work in disasters, and monitoring for security purpose. In this study, a quad-rotor is focused as a micro-UAV. The purpose of study is to investigate effects of the rotor interval on the characteristics of flow field around a quad-rotor in hovering. The velocity fields are measured by PIV. The 4-wakes past each rotor are induced toward each other and they are gathered together. It is found that the wakes are gathered to the center of all wakes with decreasing rotor interval.
