Navier-Stokes Compatible Formulation of a Database Approach for Laminar-Turbulent Transition Prediction
Résumé
This paper presents a transition prediction model that adds additional equations to the Reynolds-Averaged Navier Stokes set. It is based on the so-called N-factor method, valid for natural transition on wings due to the hypothesis it relies on (modal instabilities disturbing the boundary layer). It consists in an integration of the disturbances growth rates along the edge streamline. Herein, the disturbances growth rates are obtained via a database approach, Onera's so-called Parabolas method. Numerically, integration of the growth rates along the edge streamline is performed through additional transport equations, thus removing the need for any topology specification from the end user. Implementation caveats are illustrated on the ONERA-D airfoil in incompressible conditions. This method is then successfully applied for transition prediction on a 2D industrial laminar airfoil at transonic conditions, with varying upstream conditions and angle of attack. Satisfactory agreements with both experimental data and conventional transition predictions (LLS stability results) are obtained which illustrates the accuracy of the predicted transition location.
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