Comparative analysis of algebraic models of laminar-turbulent transition

The paper presents the results of an extensive testing of four recently proposed algebraic laminar-turbulent transition (LTT) models, which are significantly more computationally effective than differential models while being potentially on par in accuracy. The models chosen for evaluation, namely, SST KD, SST k$\gamma$, SST alg-$\gamma$ and SA BCM models, were implemented in the in-house code NTS and verified by comparing obtained results with those published by the models' authors. The experimental database used for the evaluation of the models includes transitional boundary layers at different free-flow turbulence intensities with and without pressure gradient, four airfoil flows with different LTT scenarios, and a tandem of two airfoils. It is found that at low levels of turbulence intensity, results of the SA BCM and SST k$\gamma$ models may depend on initial conditions, which does not allow to recommend them for engineering applications. The best results, comparable in accuracy to those of differential models, were obtained using the SST alg-$\gamma$ model.