Ground Effect

Ground effects can be modelled with the Lifting Line Free Vortex Wake method by mirroring all vortex elements, bound and free, at the ground plane (Leishman1). A mirror image (see Fig. 12) of all bound and free vortices is created at every time step using the ground as a symmetry plane. Such a treatment doubles the number of times that the Biot-Savart equation is calculated and thereby doubles the computational time needed for the evaluation of the convection step.


Fig. 12 Modeling of ground effect through mirroring of the wake.


J. G. Leishman. Principles of Helicopter Aerodynamics. Cambridge University Press, 2000.