Study of the Flow Around an External Fuel Tank Mounted Under a CF-18 Wing using Combined PSP and Schlieren Techniques

A wind tunnel study on a 6% scale model of the CF-18 aircraft was conducted in the Trisonic Blowdown Wind Tunnel of the National Research Council, Canada. The CF-18 model was tested with wing tip missiles, two stores mounted on the outboard pylons, external fuel tanks (EFT) mounted on the inboard pylons and semi-recessed AIM7 missiles along the fuselage sides. The pressure distribution on lower surface of the port side EFT was measured using Pressure-Sensitive Paint (PSP) at various angles of attack [-2 ° to 4 ° ], two Mach numbers [0.89 and 0.95] and two unit Reynolds numbers [6×10 6 /ft and 8×10 6 /ft]. The influence of the engine inlet mass flow rate and the effect of the port side semi-recessed AIM7 missile on the EFT pressure distribution were also determined. A focusing Schlieren system was used to visualize the flow field around the EFT, for the configuration without AIM7 and at the maximum engine inlet mass flow rate. For the first time, both the PSP and the Schlieren techniques were used simultaneously in the Trisonic Blowdown Facility.