Structure functions in a rotationally dominated turbulent flow

Structure functions are presented for the rotationally dominated flow first studied by Hopfinger, Browand, and Gagne [J. Fluid Mech. 125, 505 (1982)]. These were obtained from an image analysis of the streaks traced by neutrally buoyant particles in the fluid. In the first part of the paper the validity of the technique, first proposed by Griffiths and Hopfinger [Deep Sea Res. 31, 245 (1984)], is demonstrated. Results presented in the second part indicate a spectral distribution of energy varying like E1(k)∝k−5/2, where k is the wavenumber. The tendency toward two-dimensionality of the flow and the consequent effect on the energy dissipation rate are confirmed. The discrepancy between the measured spectral distribution and the predicted k−3 law for two-dimensional turbulence is interpreted as a result of the low Reynolds numbers achieved in the experiments.