Aerodynamic design of a light amphibious PrandtlPlane: wind tunnel tests and CFD validation

As part of the activities carried out during the "IDINTOS" project, wind tunnel tests have been performed on a ¼ scaled model of a two seats amphibious PrandtlPlane. The present paper deals with the CFD analyses performed after such experimental activities, with the main goal of solving lateral-directional stability problems observed during wind tunnel tests. In the first part of the paper, an overview of the wind tunnel test performed is provided and some of the achieved results are discussed, underlining the aforementioned directional stability problems. The second part of the paper concerns the CFD model validation activities, consisting in the search of the models whichbest represent the wind tunnel conditions. The results of several simulations are discussed, taking the influence of the scale factor, the turbulence models and the presence of wind tunnel structures, such as the walls and the strut, into account. A detailed description of the implementation procedure adopted of the κ-ω turbulence model with fixed transition is provided. Finally, in the third part of the paper, the chosen CFD model is used to find a solution for the improvement of the directional stability. The achieved result are presented and some information about the adoption of the selected solution on a scaled radio-controlled flying model are reported.