Structure and dynamics of axisymmetric tornado-like vortices simulated with a semislip lower boundary

These boundary conditions result in a poor representation of near-ground winds, which are of crucial importance for tornadoes. In this study, the boundary layer of tornadoes is investigated using more realistic semislip conditions as the lower boundary of axisymmetric, idealized simulations.

The drag law formulation of semislip conditions introduces the drag coefficient C d as a control parameter, alongside the swirl ratio S r (related to the system’s rotation) and a Reynolds number (describing diffusive effects) already employed in previous studies employing no-slip conditions. The exploration of a wide range of C d values shows that the analytical two-tiered potential vortex boundary layer is preserved under semislip conditions.