Coherent Structures of Tornado-Like Vortices

Abstract

Tornado-like vortices have distinctive characteristics that make them significantly different from atmospheric boundary flows. These dynamic characteristics are highly turbulent and unsteady which make them very complex. In this paper, it is tried to identify these dominant patterns, known as coherent structures, out of tornado-like vortex. These vortices are experimentally simulated in a 1/11 scaled model of WindEEE Dome at Western University. Coherent structures provide simplified but physical understanding of the flow. The classical method for extraction of coherent structures is proper orthogonal decomposition (POD) method. However, there are serious concerns about POD as it has orthogonality constraint. Thus, we applied another method called independent component analysis (ICA) which does not have orthogonality restrictions. This method helped us to identify non-physical POD modes and to provide a better physical description of the flow.