Studies on Tailplane Stall for a Generic Transport Aircraft Wind Tunnel Model

Abstract

A generic wind tunnel model for tailplane stall research was designed and experimentally investigated to establish a database for code validation. The configuration is numerically optimised to obtain large Reynolds numbers at the horizontal tailplane in a wind tunnel of limited size. It consists of a fuselage, a detachable horizontal tailplane and a tip-truncated wing, that mounts the model to the turntables of the closed test section. The wing was designed to reproduce a representative downwash in the tailplane region. The tests were conducted at a freestream Mach number of 0.16 and at a Reynolds number of 0.72 wx 10⁶. Tailplane stall in case of natural and fixed transition was visualised by the oil-flow technique and quantified by pressure and force measurements and by the Particle Image Velocimetry of the turbulent trailing-edge separation. Numerical simulations, using the unstructured Reynoldsaveraged Navier Stokes Code TAU, are in good agreement with the experiments. They show a separation of the boundary layer starting at the trailing edge with high crossflow velocities at the outer tailplane. Depending on the boundary-layer transition, the stall occurs abruptly for natural transition, initialised by a burst of a laminar separation bubble, or gradually for fixed transition.