Project Details
Projekt
Aerodynamic Interference of Wing Lower Side, Engine, and Pylon for High-Speed Off-Design Flow Conditions
Applicants
Dr.-Ing. Axel Probst; Professor Dr.-Ing. Ralf Rudnik
Subject Area
Fluid Mechanics
Term
since 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 406435057
The sub-project is concerned with shock-boundary layer interactions und buffet phenomena on the lower side of wing with engine nacelle and pylon. For commercial aircraft with under-the-wing mounted engines, these components cause strong flow accelerations depending on their relative positions. Especially for UHBR-engines, the related aerodynamic interference phenomena are not known. In the second phase of the project, the scientific questions are expanded to include the influence of the previously neglected engine jet and model vibrations of the XRF-1 configuration in the wind tunnel, which are made accessible for systematic research using numerical simulations. By extending the numerical methods used for this, high Reynolds numbers are now also simulated using local turbulence-resolving simulation. In addition to a basic understanding of the physical mechanisms and interactions, these investigations aim to find out to what extent the numerically and experimentally obtained results for the XRF-1 with flow-through nacelle can be transferred to real flight conditions. For this purpose, a new geometry with realistic performance parameters for a UHBR bypass engine is designed based on the flow-through nacelle considered so far and characterized with the help of efficient URANS simulations. For turbulence-resolving simulations, the hybrid RANS/LES approach established in the first project phase, which is based on local wall-modeled LES and synthetic turbulence, is extended for the consistent resolution of the engine jet and validated using measurement data from an isolated coaxial jet. With this, turbulence-resolving simulations of the jet effects on the lower-side buffet of the XRF-1 are carried out at initially moderate Reynolds numbers in order to evaluate their transferability to real aircraft configurations by comparing them with results for the flow-through nacelle. In addition, novel interference effects of the nacelle installation with the leading edge of the wing, observed in the first project phase, are investigated. Using locally turbulence-resolving simulations, the underlying mechanisms and effects on the off-design aerodynamics are investigated in detail. Regarding the methodological basis for turbulence-resolving simulations for an extended Reynolds-number range of the ETW measurements, the sub-project goes beyond the wall functions used so far and expands them to include the influence of pressure gradients at high Reynolds numbers. In this way, the turbulence-resolving investigations on the buffet on the lower side of the wing are systematically supplemented by the scaling effects of the Reynolds number, both without and with the engine jet. Finally, in order to investigate possible wind tunnel effects on the measurement data of the XRF-1 configuration, model vibrations that occurred in the ETW are reproduced and systematically investigated by forced motion URANS simulations.
DFG Programme
Research Units
