Numerical Analysis of the Unsteady Wing-Tailplane Interaction in Two-Dimensional Flows

Abstract

This article presents a study of the horizontal tailplane (HTP) buffet phenomenon, which is caused by a highly unsteady inflow of the HTP. The configuration of the wing and HTP is derived from the NASA Common Research Model. Steady results are presented which serve as a prerequisite to identify potential flow conditions in terms of HTP buffet. Subsequently, unsteady results are presented for selected low speed and high speed cases, for which the interaction between the wing and HTP are discussed. For both flow speeds, a periodic fluctuation of the lift coefficient is observed on the main wing and HTP with a dominant low frequency oscillation. For the low speed case, this oscillation is related to an unsteadiness as a result of severe separation on the upper side of the main wing, whereas the low frequent oscillation of the high speed case is attributed to transonic shock buffet on the main wing. For both cases, these mechanisms also dominate the fluctuations on the HTP segment, which is additionally influenced by high frequent oscillation as a result of vortex shedding. The latter is increasingly dominating at high angles of attack.