Small scale response in periodically forced turbulence

The response of the small scales of an isotropic homogeneous turbulence subject to periodic large scale forcing is studied using two-point closures and other simpler models. Closure results are validated by comparison with available numerical and experimental data. The phase and amplitude of the dissipation perturbations show nontrivial dependence on the forcing frequency. Perturbation methods are used to understand the basic features of this dependence. Simple finite dimensional models are found to be fundamentally incapable of reproducing the essential features of this problem.