直列に配置された円形ノズルから流出する乱流自由噴流(平均速度場)

抄録

The mean flow properties of the multiple circular jets issuing from circular nozzles in a line were investigated experimentally. The aim of this study is to clarify an effect of the arrangement pitch of the circular nozzles on the mixing and the development processes of the jets. In this study, the nozzle arrangement pitch (S/d) was set to 4.2, 2.8 and 1.4. S/d indicates a nozzle arrangement pitch which is normalized with nozzle diameter d. Reynolds number was kept constant at 25000 throughout the present experiment. The experiments were made using an X-type hot wire probe and the linearized constant temperature anemometers to measure the longitudinal mean velocity. From this experiment, it is revealed that the section of which U_ox/U_e on the x axis shows the decreasing rate of the two dimensional jet (U_ox ∝ (x/d) ^-0.5), moves toward the upstream region as decreasing with S/d.