Demonstrating the potential of CFD transition modeling for racing sailplane design

A modern racing sailplane is analyzed with computational fluid dynamics to demonstrate the utility of transitional computational fluid dynamics for sailplane design. Laminarturbulent transition is modeled with a recently developed transition model and coupled with the Spalart-Allmaras turbulence model. Coupling of the transition and turbulence models is discussed and the implementation is validated against experimental data for the winglet airfoil with strong agreement in the low drag region. The meshing strategies and problem setup used for the sailplane are outlined, including how the trim settings were determined for the computational fluid dynamics analysis. Results are presented and found to compare well with a conventional sailplane analysis tool. Regions with complex flows, such as the winglet and wing-fuselage juncture, are examined to highlight the potential for utilizing computational fluid dynamics to capture flow phenomenon and refine sailplanes in ways not possible with conventional design methods. Various component drags are evaluated and the performance is compared to aircraft without those components to demonstrate a practical use for computational fluid dynamics in sailplane trade studies.