Wing-Body Interaction: Numerical simulation, Wind-tunnel and In-flight Testing

Abstract

Wing-body interaction has been investigated by means of numerical simulation (CFD), wind-tunnel and in-flight measurements.  Aims of the turbulent separation study, verification of CFD methods and application of flow-control devices have been settled.  The sailplane wing-fuselage junction was subjected to in-flight visualization at four airspeeds and video recordings of a tuft array were acquired.  Area of boundary layer separation was determined.  The speed polar of the test aircraft was measured with an FAI International Gliding Commission approved flight recorder.  Simplified geometry, with the empennage removed, was used for CFD modelling and wind-tunnel visualization.  Analysis of both numerical and experimental data confirms lift-distribution distortion induced by the presence of the fuselage.  Passive flow-control devices were used in the junction and in-flight visualization proved turbulent separation suppression and positive influence on the sailplane performance was measured at thermalling speeds with degradation at higher speeds.  Consequently, new layout of passive devices was developed but has yet to be fully verified.