Small axisymmetric contraction of grid turbulence

Abstract

Anisotropic grid turbulence $(\overline{w^2} = \overline{v^2} \simeq \overline{u^2}/1.4)$ is passed through an axisymmetric nozzle of small contraction ratio followed by a straight section. Inside the contraction $\overline{v^2}(= \overline{w^2})$ and $\overline{u^2}$ tend to equalize, but their ratio approaches the original pre-contraction value in the straight section behind the contraction. Experiments were repeated with three grids of different mesh sizes and gave similar results.