A Symbolic-Regression-Based Amplification Factor Transport Model for Transition Prediction

An Amplification-Factor-Transport (AFT) transition model is derived by symbolic regression on a database built from two 2-D airfoil geometries over a range of Reynolds numbers and angles of attack. The regres- sion yields an explicit expression for the growth rate ¯σ = dN/ds, which is incorporated into the CFD solver CODA. The model is validated on two three-dimensional cases: the prolate spheroid and the Sickle wing of TU Braunschweig. A compressibility extension is proposed and validated on the TELFONA Pathfinder case. In all instances the predicted transition onset agrees well with experimental data for Tollmien-Schlichting mechanisms.