Abstract
To control the mixing and diffusion of the kinetic momentum in an axisymmetric turbulent jet, 6 vortex generating prominences called Vortex Generators (VGs) whose shape is half delta-wing and can generate longitudinal vortices to the streamwise direction, are applied and its effect is experimentally investigated. VGs are mounted around exit of the axisymmetric jet and their motions can be controlled independently by computer programing. In this study, VGs are operated in two active-control modes beside the passive control mode (i.e. without moving) mode: in the first active-control mode, all the VGs are oscillated radially in the same phase (Axisymmetric mode) and in the first activecontrol mode, three VGs in the opposite side to the vertical section passing through the jet centerline are put in and out to the shear layer at the nozzle exit of the jet (Alternating mode). Experimental results show that all active control modes suppress the entrainment of the ambient fluid into the turbulent jet by the change of entrainment process of the ambient fluid in the jet. It is also shown that the passive-control mode enhances the mixing near the exit.
