Lift and vortex development during transverse wing-gust encounters for a blunt-edge airfoil

This paper experimentally investigates the flowfield development and unsteady loading of a blunt-edged wing passing through a transverse gust. A gust with a trapezoidal profile was created in a water towing tank using a vertical jet. The effects of varying Reynolds number and gust strength on the leading-edge vortex (LEV) and the lift coefficients were independently investigated. The results indicate that the maximum LEV circulation increases with decreasing Reynolds number and increasing gust ratio. An analytical model for the growth of the LEV at high gust ratios was developed through integration of the convective fluxes in the shear layer. Theoretical predictions of LEV circulation and area agreed well with experimental data. The lift coefficient history of gust encounters at high gust ratios was shown to scale well with the maximum circulation of the LEV.