Hybrid RANS/LES of a generic high-lift aircraft configuration near maximum lift

Abstract

Purpose The paper aims to assess the feasibility of locally turbulence-resolving flow simulations for a high-lift aircraft configuration near maximum lift. It addresses the aspects of proper grid design and explores the ability of the hybrid turbulence model and the numerical scheme to automatically select adequate modes in different flow regions. By comparison with experimental and numerical reference data, the study aims to provide insights into the predictive potential of the method for high-lift flows. Design/methodology/approach The paper applies numerical flow simulations using well-established tools such as DLR's (German Aerospace Center) TAU solver and the SOLAR grid generator to study “Improved Detached Delayed Eddy Simulations” of the Japan Aerospace Exploration Agency (JAXA) Standard Model at two angles of attack near maximum lift. The simulations apply a hybrid low-dissipation low-dispersion scheme and implicit time stepping with adequate temporal resolution. The simulation results, including pressure distributions and near-wall flow patterns, are assessed by comparison with experimental wind-tunnel data. Findings Apart from demonstrating the general feasibility of the numerical approach for complex high-lift flows, the results indicate somewhat improved maximum lift predictions compared to the Spalart–Allmaras model, which is consistent with a slightly closer agreement with measured pressure distributions and oil-flow pictures. However, the expected lift breakdown caused by an increasing inboard separation in the experiment is not well captured. Originality/value The study not only provides new insight into the feasibility and promising potential of hybrid turbulence-resolving methods for relevant high-lift aircraft flows but also indicates the need for further research on the numerical sensitivities, such as grid resolution or flow initialization.

Grey area in Embedded WMLES on a transonic nacelle-aircraft configuration

“…The blending function σ is adopted from [4] and discerns between the well-resolved vortexdominated flow regions (LD2 ) and coarse-grid irrotational regions (Ref ). By now, the hybrid LD2 scheme (HLD2) has been successfully applied in a number of hybrid RANS-LES computations ranging from canonical flows on structured grids [11] to complex high-lift aircraft on mixed-element unstructured meshes [14].…”