Experimental investigation of the influence of different helicopter ramp geometries on the wake structure

Abstract

In this work, the influence of two different rear fuselage upsweep geometries on the aerodynamic characteristics of a multipurpose medium lift helicopter fuselage is investigated. The fuselage geometry was very similar to Mil Mi-8 helicopter fuselage. The balance measurements, which were obtained at T-1K wind tunnel of KNRTU-KAI named after A.N. Tupolev, were supplemented with PIV measurements. Obtained results indicate that the flat ramp has higher drag coefficient values at negative angles of attack, compared to conventional rear fuselage upsweep geometry. The vortex core circulation of the vortices, obtained from PIV velocity fields showed the flow field behind the flat ramp of the fuselage had much higher vortex circulation values compared to conventional rear fuselage upsweep.