Abstract
Homogeneous turbulence was subjected to plane strain in a distorting tunnel of maximum strain ratio 13:1. The turbulence was generated by using bi-planar grids of square bars with different solid fractions and a range of mean flow velocities, so that relative strain rates could be varied by about a factor of three; relative strain rate being here defined as the ratio of strain rate to initial eddy turnover rate. The change in anisotropies of the turbulence intensities and also of the velocity derivatives are found to depend strongly on the relative strain rate and so does the change in turbulent kinetic energy. This dependency is explained in terms of the ratio of turbulence production to dissipation rates which are related to the relative strain rate. An interesting feature is the inflexion in the anisotropy versus strain ratio curve observed for low relative strain rates. This is thought to be a result of an `overshoot' of pressure strain rates.