 inviscid-incompress flow theori static peripher jet proxim ground inviscid-incompress flow theori static peripher jet proxim ground exact flow theori peripher jet issu symmetr hover aerial-ground vehicl present theori exact insofar simplifi assumpt obtain solut govern inviscid two-dimension hydrodynam flow equat valid jet thick vehicl height ratio limit applic exist theori low thick height ratio defin jet reaction lift power coeffici static condit introduc comput lift augment lift power ratio calcul applic three-dimension vehicl rotat symmetri indic 