Interfacial Mixing Driven by Mean Shear and Oscillating Grid

Abstract

Much work is done to understand the mixing processes at a density interface. Laboratory studies commonly rely on experiments where entrainment is driven by either a mean shear or by a vertically oscillating grid. Although these experiments provide useful results, it is suggested that neither of these setups is completely representative of conditions in natural water bodies. The present study investigates a more general situation where the relative magnitudes of mixing generated by these two sources of energy are varied in order to better understand the differences in entrainment results reported for the two different kinds of experiments. A series of experiments is performed and a semiempirical model is developed to predict the entrainment measured in these tests. The model is based primarily on energy considerations and accounts directly for the mixing energy introduced by each of the mechanisms under consideration. The model agrees well with the data and also with data from a previous wind‐mixing experiment. Finally, application of the results to general entrainment modeling is discussed.