Influence of the initial conditions at nozzle exit and acoustical action on the structure and stability of a plane jet

Abstract

Victor V. Kozlov, Genrich R. Grek*, Yury A. Litvinenko, Grigory V. Kozlov, & Maria V. Litvinenko Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch of the Russian Academy of Sciences 4/5, Institutskaya str., Novosibirsk, 630090 Novosibirsk Region, Russia *Corresponding author: Genrich R. Grek, E-mail: grek@itam.nsc.ru The results of experimental investigations of the influence of the initial conditions at the nozzle exit and acoustical action on the structure of a plane jet, the characteristics of its evolution and stability are presented in this work. Peculiarities of the development of laminar and turbulent plane jets are shown for the same Reynolds number. Patterns of smoke visualization of the jet upon variation of the initial conditions of jet formation and acoustical action, and during the interaction of streaky structures with vortices of the laminar plane jet vortex street are discussed. Laminar and turbulent jets at the exit of a two-dimensional Hagen–Poiseuille channel are found to experience longitudinal sinusoidal oscillatory motion considered as a whole. Peculiarities of evolution of both laminar and turbulent jets under acoustical action are revealed. It is found that the generated symmetrical mode of instability of a laminar plane jet is suppressed by the asymmetrical mode of instability. The interaction of the streaky structures, generated on one side of a plane nozzle, with the vortices of a laminar plane jet with a parabolic mean velocity profile is shown to lead to the generation of Λor Ωlike vortices on both the left and right vortices of the vortex street. The results of the investigations are valid for jet flows with small Reynolds numbers.