Fifth High Lift Prediction Workshop: Wall-Modeled Large-Eddy Simulations Technology Focus Group Summary

Analysis and summary of over 500 large-eddy simulations representing submissions from 12 distinct numerical solvers and three distinct grid topologies submitted to the Wall-Modeled Large-Eddy Simulations Technology Focus Group of the 5th High Lift Prediction Workshop (HLPW-5) are provided. The focus is on assessing the potential of wall-modeled large-eddy simulations (WMLESs) to accurately predict aerodynamic loads on high-lift aircraft configurations under landing and takeoff conditions. The simulations were based on the NASA High-Lift Common Research Model (CRM-HL) ecosystem and explored several distinct model geometries, including a “clean-wing” configuration, as well as a typical “landing configuration” with extended flaps, slats, and a nacelle with a chine/vortex generator intended to increase the maximum lift ([Formula: see text]) and extend the onset of aerodynamic stall to higher angles of attack. The results are encouraging; “blind” numerical simulations showed favorable agreement with experimental data obtained by Mouton et al. (“Test Summary of the Full-Span High-Lift Common Research Model at the ONERA F1 Pressurized Low-Speed Wind Tunnel,” AIAA Paper 2023-0823, 2023) at ONERA, with reasonable agreement in both flow-separation patterns and the integrated force and moment coefficients. While some coarse-grid outliers were observed, most submissions were within 2–3% of each other for [Formula: see text] prediction for the most complex case studied (slats, flaps, and nacelle) at three different Reynolds numbers ([Formula: see text]) ranging from a subscale value of [Formula: see text] through a flight-scale value of [Formula: see text], although differences of this magnitude may still be important for WMLES utilization toward certification by analysis. However, some challenges remain—most notably the prediction of laminar-to-turbulent transition under high pressure gradients. Simulations employing fully turbulent wall-stress closures everywhere appear to show large sensitivity to grid resolution, numerical discretization, as well as SGS closure when predicting clean-wing flows. Evidence of this is seen in disparate stall onset mechanisms predicted for clean-wing flows as well as premature slat transition and the subsequent loss of lift at [Formula: see text] in some simulations. Low-[Formula: see text] [Formula: see text] predictions on configurations with extended flaps also remain a challenge, with some simulations underpredicting the extent of flap separation and others showing some degree of error cancellation.