The effect of aspect ratio on statistically-stationary homogeneous shear flow

The effect of the aspect ratio of the numerical domain is investigated in homogeneous shear turbulence at moderate $Re_\lambda=40\mbox{-}100$, over long times for which its length scales are constrained by the numerics. For $L_y/L_z>1$, the cross-shear box size, $L_y$, has a negligible influence on the statistics. For $A=L_x/L_z\le 2$, the flow contains a relatively steady streamwise-velocity $(u)$ streak, and the r.m.s. $u'$ dominates the energy. For $A\ge 2$, the integral length is proportional to the spanwise box size $L_z$ and the r.m.s. velocities are proportional to $SL_z$. That regime is dominated by strong bursting. In $2