This spreadsheet is an Excel/VBA translation of a Fortran program from C.Y.Chow’s An Introduction to Computational Fluid Mechanics. The program tracks the motion of wingtip vortices. It shows their motion as induced by each other and influenced by the nearby ground and the ambient crosswind. The user can change the crosswind speed, wingspan, mass and velocity of the aircraft and watch the impact on the subsequent motion of the vortices. The simple model includes no dissipation of the vortices.  Of course, it is well known that trailing vortices may be long-lived and dangerous to following aircraft.

The method of images accounts for the presence of the ground.