Interfacial Mixing Caused by Turbulent Buoyant Jets

Abstract

Laboratory experiments were carried out to investigate mixing and entrainment induced by a planar turbulent buoyant jet impinging on a stable density interface. The jet was released horizontally into the homogeneous bottom layer of a fluid system in which the top linearly stratified layer was separated from the homogeneous layer by a density discontinuity. This flow configuration has similarities to those that occur in solar ponds and ocean thermal energy conversion plants. The results reveal markedly different entrainment mechanisms, and thus entrainment laws, for different jet regimes that depend on the inlet buoyancy of the jet. Measurements included the entrainment velocity, interfacial‐layer thickness, and time evolution of vertical density profiles. Based on observations of entrainment mechanisms, simple theoretical models are developed to predict entrainment laws for slightly buoyant and neutrally buoyant jet regimes, and the model predictions are compared with the experimental results.