An experimental study of elevated round jets deflected in a crosswind

Flow structures and turbulence properties of the elevated jets in a crosswind are experimentally studied via the laser-light sheet smoke-pattern flow visualization technique and laser Doppler velocimeter. Smoke patterns, velocity vectors, and streamlines are superimposed to clarify and compare the flow structures at different jet-to-crosswind momentum flux ratios. Four flow structures with apparent differences are identified. They are downwash, crosswind-dominated, transitional, and jet-dominated flows. Large amount of jet fluids in the downwash and crosswind-dominated flows are entrained down to the tube wake because a clockwise-rotating vortical structure is formed in the near wake due to the combined effects of the jet shear and tube-tip downwash. In the transitional and jet-dominated flows, the up-flows induced by large up-shooting jet velocities overwhelm downwash effect so that most of the jet fluids go downstream rather than to the tube wake. The jet fluids of the transitional and jet-dominated flows thus can transport and disperse to far field. The iso-vorticity contours are superimposed to the streamlines patterns to compare the vorticity-concentrated locations with the features of the flow structures. Distributions of average velocity components and turbulence intensities in the near wake are presented and discussed to improve the understanding of the flow characteristics. [Copyright &y& Elsevier]