Flow Field Investigations on the SACCON Configuration in Stationary and Pitching Mode by Means of Particle Image Velocimetry

Abstract

For the design of Unmanned Combat Air Vehicles (UCAV) the understanding of vortex dominated flow topologies above delta wing configurations constitute an important aspect. Complex flow patterns (vortex onset, development and interactions) are already present for delta wings in steady flight, and can cause adverse unsteady loading effects induced by vortex structure interactions. Such effects are even further complicated when the delta wing undergoes dynamic motions. Computations on unsteady UCAV configurations and motions are challenging. For unmanned vehicles g-force restrictions of the human are waived, i.e. enabling more complex dynamic motions and inherently more complex flow phenomena. Yet, even for normal dynamic motions unsteady flow phenomena are induced by the complex vortex interactions. In the present paper the three dimensional flow fields above a stationary and pitching Unmanned Combat Air Vehicle (UCAV) model are investigated using velocity and vorticity distributions obtained by Stereo-PIV measurements. Within the scope of NATO/RTO Task Group AVT-161 the SACCON (Stability And Control CONfiguration) model is used for analyzing synergetic design criteria and to reduce the timescale of design phase by integrating computational and experimental analyses early in the design chain. The aim of the PIV experiments is to provide flow field data for the validation of CFD computations, the determination of complex flow topologies, and the investigation of the vortex flow above the SACCON configuration responsible for non-linear effects.