This paper reports on a numerical investigation of the use of trailing edge circulation control as a roll effector on a generic unmanned combat aerial vehicle (UCAV), the DLR-F19 Stability and Control CONfiguration (SACCON). The coanda effect induced by fluidic injections at the trailing edge of a wing is used to increase circulation and generate lift. RANS predictions have been validated against wind tunnel experiments conducted at the Georgia Institute of Technology and NASA's basic aerodynamic research tunnel on an aerofoil employing trailing edge circulation control. Two turbulence models were used, the Wilcox k-ω model and Menter's Shear Stress Transport, showing that the Wilcox k-ω model provides the best comparisons with the experimental data. Baseline data for the SACCON with conventional control surfaces from wind tunnel experiments done at the DNW-NWB wind tunnel are used to ensure the correct flow features are being modelled for the flows encountered by this type of UCAV and to provide a comparison for the performance of the circulation control devices. Modifications have been made to the DLR-F19, replacing the conventional control surfaces with trailing edge circulation control of the same spanwise extent. This includes two configurations, one with a single slot and one with three slots of equal width along the wing. The circulation control performs well at low angles of attack producing a similar roll moment to the conventional control surfaces. Due to the flow separation at the high angles of attack the circulation control is unable to generate a rolling moment. Finally, the flow topology is examined to understand the causes of the decrease in the performance.

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The ability of computational fluid dynamics to predict the steady and unsteady fluid flow over a generic UCAV configuration, with and without control surface deflections, at off design conditions is investigated. The complex, non-linear flow, various combinations of control surface deflection and the presence of multiple interacting vortices on the flow histories provides a challenging test for current capability. A range of static and dynamic test cases have been computed, for both low and high speed flows, for comparison with experimental data, obtained as part of the NATO STO AVT-201 Task Group. The simulations are performed using a multiblock code to solve the Reynolds-Averaged Navier-Stokes equations; and the control surfaces are modelled with a deformed mesh and blended gaps that simplify the geometry. These tests will provide an assessment of the ability of computational fluid dynamics to evaluate such flows, and will allow for deficiencies in the state of the art to be identified.