Refuelling tanker aerodynamics and hose characteristics

Abstract

The present work is conducted within the context of air to air refuelling technologies and aims at the development of an understanding of a typical refuelling tanker wake like that of an A330 [54] and the A400M [54]. The wake is particularly investigated within the near field and extended near field wake regions in close vicinity to the rear fuselage. Moreover, the interaction between the wake and the refuelling hose is studied including the resulting hose characteristics. A number of refuelling conditions and aircraft models are considered for the investigation of the wake. Moreover, an arbitrary hose fairing model is considered to study the effect of the fairing on the flow field and the refuelling hose. Different refuelling configurations are taken into account for the investigation of the hose characteristics. Various hose exit positions were studied within the near field wake to assess the impact on the hose characteristics. The probe hose engagement with the associated hose whip phenomenon is a major topic within this work. The hose whip is a highly undesired phenomenon and is amplified by a specific hose shape which is characterised through an inflection point along the hose. The present research reveals that the rear fuselage wake has a crucial impact on the hose characteristics. In particular, the rear fuselage upwash is the primary cause for formation of the undesired hose inflection point. The findings obtained from the present research are used for the suggestion of palliatives to avoid undesirable hose characteristics. In particular, there is one approach recommended which aims at the avoidance of a hose-upwash interaction. It leads to the suggestion of a circumferentially shifted and radially displaced hose exit and deployment of the refuelling hose.