Relation between enstrophy production and geometry near the turbulent/non-turbulent interface in free shear flows etc15 Tracking Number 283Presentation: Session: Jets and Wakes 1 Room: Room E Session start: 10:30 Tue 25 Aug 2015 Tomoaki Watanabe watanabe.tomoaki@c.nagoya-u.jp Affifliation: Nagoya University Carlos da Silva carlos.silva@ist.utl.pt Affifliation: Instituto Superior Técnico Yasuhiko Sakai ysakai@mech.nagoya-u.ac.jp Affifliation: Nagoya University Kouji Nagata nagata@nagoya-u.jp Affifliation: Nagoya University Topics: - Jets and wakes Abstract: In many free shear flows, such as mixing layers, wakes and jets exhibit a sharp turbulent/non-turbulent interface (TNTI) separating regions of turbulent and non-turbulent or potential flow. In the present work the dependence of enstrophy production on the interface geometry near the TNTI is investigated by using direct numerical simulations (DNS) of a shear free turbulence (SFT) and a temporally developing planar jet (PJET). It is shown that the geometry of the TNTI has impacts on the mechanism governing enstrophy dynamics within the interface layer itself. In particular it is shown that enstrophy production within the turbulent sublayer is primarily associated with a convex shape of the interface both the SFT and PJET. |