On the relationship between vortex tubes and sheets in wall-bounded flows

Abstract

The statistical relationship between vortex tubes and vortex sheets in turbulent wall-bounded flow is analyzed by means of conditional averaging of DNS fields. The results support strong association between the two types of coherent structures, and indicate that vortex tubes are produced upon roll-up of vortex sheets (as in the hairpin vortex paradigm), or interact causing the ejection of near-wall vorticity, or generate sheets of streamwise vorticity through a rubbing effect caused by the no-slip condition.