Abstract: A gas turbine engine is proposed which comprises a bypass duct, a core engine, and a fluid mixing arrangement. The fluid mixing arrangement is configured to mix a bypass flow of fluid and a secondary flow of fluid, the secondary flow of fluid being drawn from the core engine. The arrangement comprises a flow duct terminating with an outlet and being arranged to direct said secondary flow through the outlet and into the bypass flow. The arrangement is characterised by the provision of a wing in the region of the outlet, said wing extending at least partially across the duct and being configured to generate lift from said secondary flow effective to produce at least one trailing vortex extending into said bypass flow. The fluid mixing arrangement can be used as a ventilation arrangement or as part of a bleed valve arrangement in the gas turbine engine.