INFLUENCE OF INITIAL CONDITIONS AT NOZZLE SECTION ON FLOW STRUCTURE AND INSTABILITY OF PLANE JET

Read more Experimental data concerning the influence of initial conditions at the nozzle exit on the structure and development characteristics of plane jet are reported. Features in the development of laminar and turbu-lent round jets emanating from variously elongated nozzles at identical Reynolds numbers are revealed. Smoke visualization pictures obtained for jets formed under different initial conditions (with different distributions of mean and pulsating flow velocities at the nozzle exit), influence of acoustic and interac-tion of streaky structures with vortex trail of laminar plane jet are discussed. It is established that, the laminar and turbulent jet on an output of the plane channel of Hagen-Poiseuille undergoes sine wave os-cillations, as a single whole. It is established that, the symmetric mode of instability of a laminar plane jet are suppressed asymmetrical. It is shown that, interaction of the streaky structures generated on one side of plane nozzle, with vortices of a laminar plane jet with a parabolic velocity profile leads to appearance of Λ- or Ω-vortices on vortices of a vortex trail, on the right as well as on the left side of the nozzle.

Keywords:
plane jet, coherent structures, instability, receptivity, smoke visualization, hot-wire ane-mometer.
УДК 532.526

INFLUENCE OF INITIAL CONDITIONS AT NOZZLE SECTION ON FLOW STRUCTURE AND INSTABILITY OF PLANE JET