Implementation, verification and validation of empirical transition criteria for airfoil and rotary wing applications using the DLR FLOWer code.

Abstract

This report covers the implementation, verification and validation of a transition prediction method for airfoil and rotary wing applications based on the DLR-FLOWer code. The prediction method features five empirical criteria according to minimum pressure, laminar separation, Michel, van Driest & Blumer and Arnal, Habiballah & Delcourt (AHD). The criteria’s equations will be briefly summarized. The prediction method’s algorithm and it’s implementation into the DLR’s structured flow solver FLOWer will be described. Validation has been carried out for the Somer’s airfoil (M∞ = 0.3, α = [−5◦ , 15◦]) as well as the CAST10 airfoil (M∞ = 0.73, α = −0.25◦ ). A verification of the implemented method has been done using the ONERA 7A rotor hover test case. Finally, the method is applied to a recent rotor geometry in hover, representing an industrial application case.