Interaction Mechanism of Vortex System Generated by Large Civil Aircraft Afterbody

摘要

The evolution of vortex system in the wakes of the simplified largerncivil aircraft afterbody is simulated with the improved delayed detachedrneddy simulation (IDDES) method and adaptive mesh refinement technology.rnFirst of all, the physical characteristics of afterbody vortex system arernpresented to perform qualitative analysis. Results based on two-dimensionalrnkinematic analysis demonstrate that three phases show up in vorticalrninteraction including formation, wake evolution and wake interaction.rnFurther, two patterns of vortical interaction are clearly identified as follows:rnstrong straining interaction (SSI) and strong rotating interaction (SRI).rnCompared with SRI, SSI features considerable circulation decrease of 20%rnin formation phase and interaction intensity reduction of up to 45% atrndownstream wake location of eight-characteristic length. It is attributed tornthat the circulation of afterbody primary vortex pair (APVP) has declined inrnformation phase due to the remarkable stress deformation imposed byrnhorizontal tail root vortex pair (HRVP) in SSI, whereas the tip vortex pairrn(HTVP) obtains a circulation augmentation for more dramatic convectiverndiffusion and fluid entrainment in SRI. Above all, the inner connectionrnbetween kinematic characteristics and vortex induced drag is revealedrnquantitatively, which offers a novel perspective to reduce crusing resistancernof aircraft afterbody.