Influence of sidewalls on the centerline small-scale turbulence of a turbulent high-aspect-ratio rectangular jet

• A slot jet confined between two sidewalls is compared with that without sidewalls.
• The small-scale turbulence differs in the two jets.
• The effect of sidewalls is weaker on small-scale than large-scale turbulence.

This study experimentally investigates the influence of placing two parallel sidewalls confining a high-aspect-ratio rectangular jet on the centerline turbulence of various scales, such as the Kolmogorov and Taylor scales. Measurements were made by hot-wire anemometry at a jet-exit Reynolds number of 7000. It is found that the small-scale turbulence of the jet configured with sidewalls appears to statistically differ from that without sidewalls in both the near-field and far-field flow. The Kolmogorov scale is found to attain the asymptotic state over a shorter axial distance than does the Taylor scale. This suggests that the extent of influence of varying the boundary conditions on the large-scale flow is stronger than that on the small-scale turbulence.