Unsteady Tailplane Loads From the Wake of a Stalled Wing Using Concurrent PIV and Force Measurements

This study experimentally investigates the unsteady aerodynamic loads imposed on a horizontal tailplane immersed in the wake of a stalled, finite wing. A low aspect ratio swept wing was tested at high angles of attack (20–30 degrees) which exhibited partial or full aerodynamic stall, and its wake structure was characterized through 7-hole probe measurements, timeaveraged PIV, and spectral analysis. The stalled wing was found to produce multiple vortex types that induce large flow angularities, high turbulence intensities, and distinct shedding frequencies in the 125–165 Hz range. By traversing the tailplane vertically through the vortical wake, this work quantifies the resulting lift, drag, and pitching-moment responses of the tailplane. Time-averaged results reveal strongly negative tailplane lift and nose-up pitching moments across all positions due to wake skew and downward momentum transfer produced by the front wing. Time-resolved PIV and load measurements showed that vortex impingement produces fluctuations in lift coefficient of 0.2 from the vortex shedding frequency bands. These findings provide new experimental insight into wing–tail aerodynamic interactions in stall, complementing prior computational studies and informing future design considerations for aircraft components operating in highly separated flow environments prone to fatigue.