Validation of Boundary-Layer-Transition Computations for a Rotor with Axial Inflow

Kurzfassung

Boundary-layer-transition computations are performed using the in-house finite-volume solvers elsA by ONERA and TAU by DLR. Reynolds-averaged Navier-Stokes simulations, using the Langtry-Menter model as well as semiempirical transition criteria, are presented using both solvers for a rotor in climb. The numerical results are compared to temperature-sensitive paint experiments conducted at DLR's rotor test facility. Concerning the Langtry-Menter computation, transition occurs with both solvers due to laminar separation close to the trailing edge, further downstream than seen in the experiment. Semi-empirical transition criteria predict transition within both codes due to laminar separation, which was not detected in the experiments. When only considering the AHD criterion, the transition locations within the numerical simulations and the experiment are in good agreement along the entire span in all three considered test cases. In addition, numerical results are presented for a test case with cyclic pitch. These unsteady boundary-layer transition computations are carried out using the semi-empirical transition criteria approach of DLR-TAU. In accordance with the static test cases, the results are promising, as long as the laminar-separation criterion is deactivated.