Towards CFD Validation for 3D High Lift Flows - EUROLIFT

Kurzfassung

The major purpose of the European High Lift Programme EUROLIFT is a common assessment of CFD code capabilities with respect to the aerodynamic simulation of the flow field of 3-dimensional high lift transport aircraft configurations. The present contribution describes the status of the theoretical workpackage (WP2) of EUROLIFT at roughly half of the project's duration. The theoretical investigations cover the aspects CFD code assessment, code improvement, and transition prediction. These activities are being accompanied and supported by two experimental workpackages for validation (WP1) and verification (WP3) wind tunnel tests. The main objectives are a common assessment of European state-of-the-art CFD codes for 3-dimensional high lift flows in general and the simulation of the Re No. influence up to flight conditions in special. Accompanying to the main focus, that is laid on 3-dimensional studies, 2-dimensional computations of high lift airfoils are carried out, either in order to validate the different CFD codes used by the EUROLIFT partners in continuation of preceding common studies, as well as to demonstrate code improvements provided throughout the project runtime, before applying them to the much more complex 3-dimensional test cases. Concerning the simulation of 3-dimensional flows, aspects such as CAD-CFD geometry refurbishing, structured and hybrid unstructured grid generation for the transport aircraft configurations are discussed. First results of corresponding Navier-Stokes computations are presented. In order to separate in a first step the assessment of the numerical simulation quality from the influence of transition effects, the RANS computations are carried out either assuming fully turbulent flow or detected transition locations from the experiments, if available. Nevertheless, due to the importance of transition prediction corresponding studies are conducted within EUROLIFT for an untapered swept 3-element wing.