Measurements of the growth of a turbulently mixed layer in a linearly stratified fluid

Measurements have been made of the growth of a turbulently mixed layer in a linearly stratified fluid for Brunt–Väisälä frequencies N in the range 0.099–0.386 Hz. Turbulent mixing was induced by a horizontal grid undergoing vertical oscillations at frequencies f in the range 5.3–20.5 Hz. The experimental results support a theory due to Long which predicts the size of the mixed layer D measured from a ’’virtual’’ source plane, as a function of time t, given by D∝f1/2 N−7/18 t1/9.