03.1 - Aerodynamics – CFD Methods and Validation
OPTIMISATION OF VORTEX GENERATORS FOR STALL SPEED REDUCTION
J. Meyer¹, P. Okfen¹, C. Bil¹; ¹RMIT University, Australia
To make the Cessna 208 Caravan more suitable for the challenging missions of MAF International in Papua New Guinea, where short runways and tall surroundings necessitate high lift at low speeds, the application of vortex generators was investigated. An extensive literature review revealed eight geometric or direct design parameters which could be attributed to different physical effects. These could subsequently be condensed into three indirect design parameters governing vortex generator design, namely range of efficacy, kinematic energy input and drag. It was determined that strong interdependencies between the direct design parameters necessitate a numerical study to cover the entire design space. Optimisation via surrogate modelling was identified as a suitable approach. After 3D-Laser scanning the geometry, preliminary CFD studies hinted at limited potential for lift increase, as little flow separation was observable. Design optimisation of a Kriging surrogate model based on 60 sampling points confirmed these assumptions yielding a maximum lift increase of 1.22% at an angle of attack of 14°.