Suction vortices and spiral breakdown in numerical simulations of tornado‐like vortices

Three‐dimensional simulations of tornado‐like vortices are presented. The simulations are from a numerical model of the incompressible Navier‐Stokes equations, with a Reynolds number, based on scales of the entire recirculating updraft, of up to 4.0 × 104. In a companion axisymmetric model, the theory for the corner flow swirl ratio provides an excellent prediction of the results. For the three‐dimensional nonaxisymmetric model, the corner flow swirl ratio is not easily applied a priori, but nonetheless provides a framework for identifying a consistent departure of the three‐dimensional simulations from the axisymmetric simulations.