Towards Virtual Flight in Realistic Environments: A Hybrid Coupled Simulation Method

Abstract

The vision of establishing a simulation system for virtual flight in a realistic environment is addressed by the coupling of two separate flow solvers in a bidirectional manner. In the long run, this shall enable (for example) the simulation of a flight through realistic atmospheric turbulence, including the effects on the aircraft and the rollup of trailing vortices and their further development until final decay. A compressible Reynolds-averaged Navier–Stokes (RANS) solver resolves the near field around a vortex generator (a rectangular NACA0012 wing geometry), including its boundary layer. An incompressible large-eddy simulation (LES) solver is used to model the atmosphere around the vortex generator, with its wake footprint in the LES domain being of primary interest. Two validation cases are presented. First, the method is partially validated with data from a wind-tunnel experiment. The second case is a vertical gust-wind simulation, which is compared to an already validated pure RANS approach for calculating the global aerodynamic coefficients given analytically defined atmospheric disturbances. The hybrid method proves to be powerful in cases where large-scale transient atmospheric effects and their interaction with flying aircraft are to be studied.