Transition prediction for the NASA CRM-NLF with the eN-method using incompressible and compressible linear stability analysis

Abstract

Temperature sensitive paint images from a wind tunnel campaign for the CRM-NLF geometry are used to extract experimental transition lines to be used to determine critical N-factors based on incompressible and compressible linear stability theory. Transition locations are subsequently predicted for different flow conditions using RANS computations and linear stability theory in form of the the eN-method. For the stability analyses, the laminar boundary layer data are computed using a boundary layer code for swept, tapered wings. For the transition prediction a sensitivity analysis is performed that takes into account varying critical N-factors and angles of attack. Additionally, the effect of artificially including the turbulent wedges from the experiment in the numerical simulation is investigated. A general good agreement between predicted transition fronts and experimental data is shown which is further improved by adequately adjust the flow conditions in the simulations.