Embedded WMLES of Shock/Boundary-Layer Interaction on a Nacelle-Aircraft Configuration

Research on a long-range transport aircraft with ultrahigh bypass ratio (UHBR) nacelles at transonic flow conditions is presented. In this context, different numerical as well as experimental methodologies are employed. A major research issue is the aerodynamic interaction of the flow field with the UHBR nacelle, pylon, fuselage, and wing lower side at negative angles of attack. The interactions of transonic shocks with the boundary layer are analyzed by Reynolds-averaged Navier–Stokes (RANS) simulations with regard to flow separation and recirculation. Further investigations are performed for a transonic shock on the outside of the nacelle with turbulence-resolving simulation approaches. For this purpose, two embedded wall-modeled large-eddy simulation methods based on different RANS background models (Menter’s shear stress transport model and Reynolds stress equation model) in combination with a synthetic turbulence generator are employed. This allows analysis of the dynamics of the shock front with regard to shock buffet. The results are compared to experimental data of pressure sensors, unsteady pressure-sensitive paint and particle image velocimetry measurements obtained in wind-tunnel testing at the European Transonic Wind Tunnel. Furthermore, the impact of the angle of attack on the shock/boundary-layer interaction is evaluated. The numerical and experimental data show consistent results in terms of shock positions and shock dynamics.