The TELFONA Pathfinder Model, a second look

Abstract

Within the European Project Telfona the Pathfinder Model was designed, analyzed numerically, constructed and tested with the aim to obtain the capability of laminar flow testing of the European Transonic Wind Tunnel (ETW). The model was designed for natural laminar flow (NLF) for transonic flow conditions with high Reynolds number. Pre-test numerical analysis results demonstrated that the Pathfinder wing pressure distribution was adequate to provide calibration test points. The ETW tests provided pressure distribution data and transition position obtained from images using the Cryogenic Temperature Sensitive Paint Method (cryroTSP). The evaluation of this data with several transition prediction tools was used to establish the transition Nfactor values for ETW. In this work, after test CFD solutions are obtained using numerical Navier-Stokes solutions. Stability analysis is performed using the local stability 2-N factor method. In the first part of this work, it is shown that for the range of flow conditions tested, the Pathfinder wing pressure distribution is sufficiently insensitive to different parameters like span, transition position and turbulence model. In the second part, it is shown that for selected flow conditions a good agreement is obtained between stability analysis based on experimental data and numerical data. In the third part the numerical analysis and experimental data are used complementarily.