Numerical Aspects of Transition Prediction for Three-Dimensional Configurations

Abstract

The feasibility to predict transition for three dimensional configurations is presented by means of a coupled program system consisting of a 3D Navier-Stokes solver, a transition module and a stability code. The assumption to use inviscid streamlines as integration paths for the N-factor calculation makes it possible to use linear stability theory in a straightforward way for three dimensional flows. The developed transition module has been adapted to be used with sequential and parallel computations to account for the increased computational demand for three dimensional configurations. Detailed investigations have been carried out, to show the ability of the Navier-Stokes code to provide data of three dimensional boundary layers of high accuracy needed for the stability analyses. Applications of the transition prediction method using the 2N-factor method for the case of an inclined prolate spheroid shows reasonably good results compared to experiments. First application of the transition prediction tool on a generic transport aircraft show promising results for the ability to predict transition on complex geometries.

Evaluation of a Correlation-Based Transition Model and Comparison with the eN Method

“…The widely used e N method [1,2] for transition prediction is based on local, linear stability theory and is the standard transition prediction method [3][4][5][6] in the hybrid Reynolds-averaged Navier-Stokes (RANS) solver TAU [7][8][9][10] of the German Aerospace Center (DLR). The method requires nonlocal boundary-layer quantities like the disturbance growth along streamlines that are not directly accessible in RANS-based computational fluid dynamics (CFD) codes.…”

Transition on a Wing with Spanwise Varying Crossflow and Linear Stability Analysis

“…Afterward, this calculated solution of the base flow was used to extract laminar boundary-layer data for stability analysis, following a number of outer streamlines as described in [21]. Note that the laminar boundary layer in the three-dimensional (3-D) RANS solution was resolved with 120 points in the wall-normal direction to achieve a reasonable resolution of the inflectional crossflow velocity profiles [22]. The results in Figs.…”

Development and Application of Transition Prediction Techniques in an Unstructured CFD Code (Invited)

“…The streamline-based transition prediction approaches are realized through a transition prediction module implemented directly into the TAU RANS solver [35,[112][113][114].…”