An experimental study of a turbulent jet impinging on a flat surface

The flow characteristics of an isothermal turbulent jet impinging normally on a flat plate was studied experimentally using hot-wire anemometry. The air jet discharged from a round pipe with an inner diameter D and the distance between the pipe exit and the flat impingement plate was 9D. The Reynolds number, based on the jet centerline velocity at pipe exit and the pipe inner diameter, was 10,338. Measurements were performed in the free- and wall-jets, mean velocity, RMS, Reynolds shear stress, higher-order moments of velocity fluctuations, dissipation spectrum as well as spatial characteristic scale results being presented. The scales in the center of the mixing region have the most energy, from which the scales belonging to the inertial range have a trend to shift to the larger scales with the increasing radial traverse, thus the scales of the coherent structures belonging to the dissipation region get more as welt as larger. The scales belonging to the inertial range in the wall-jet region tend to the larger scales with the increasing normal traverse.