  A hypothesis is tested and validated for predicting the vortex strength
induced by a vortex generator in wall-bounded flow by combining the knowledge
of the Vortex Generator (VG) geometry and the approaching boundary layer
velocity distribution. In this paper, the spanwise distribution of bound
circulation on the vortex generator is computed from integrating the pressure
force along the VG height calculated using CFD. It is then assumed that all
this bound circulation is shed into the wake to fulfill Helmholtz's theorem and
then curl up into one primary tip vortex. To validate this, the trailed
circulation estimated from the distribution of the bound circulation is
compared to the one in the wake behind the vortex generator determined directly
from the wake velocities at some downstream distance. In practical situations,
the pressure distribution on the vane is unknown and consequently other
estimates of the spanwise force distribution on the VG must instead be applied,
such as using 2D airfoil data corresponding to the VG geometry at each
wall-normal distance. Such models have previously been proposed and used as an
engineering tool to aid preliminary VG design and it is not the purpose of this
paper to refine such engineering models, but to validate their assumptions such
as applying a lifting line model on a VG that has a very low aspect ratio and
placed in wall boundary layer. Herein, high Reynolds number boundary layer
measurements of VG induced flow were used to validate the Reynolds Averaged
Navier-Stokes (RANS) modeled circulation results and are used for further
illustration and validation of the hypothesis.
