Effect of grid generated turbulence on near field characteristics of round jets

The effect of the small scale turbulence on the development of the round jet is experimentally studied using hot wire anemometry. The small scale turbulence is generated by placing a grid having grid spacing near the nozzle exit. Experiments are carried out for the range of Reynolds numbers (4000, 6000 and 8000). It is observed that the small scale structures present in the jet slows down the jet mixing characteristics and there by retards the decay rate in the near-field region. It is observed that in the grid disturbed jets, the ratio of the turbulent kinetic energy to mean-flow kinetic energy is relatively lower than that of the undisturbed jet without any grid. From the spectral analysis, it is observed that the grid disturbed jets has higher energy content than that of the undisturbed jets. © 2013 by Walter de Gruyter Berlin Boston.