Surface Thermal Plume in Channel

Abstract

The summer behavior of a surface thermal plume in a deep channel is investigated. An integral model is applied to predict the supercritical flow domain. The model is based on the concept of turbulent entrainment decay in stably stratified shear flows. The performance of linear and nonlinear entrainment functions are evaluated. The turbulent structure of the plume is examined using flow visualization and measurements of temperature fluctuations. When the plume attains its terminal phase, the collapsing turbulence is characterized by a gradual disappearance of small‐scale fluctuations and the appearance of coherent thermal waves. This transfer of energy to lower frequencies and the associated organization of fluctuations coincide with a shift in the pattern of turbulent energy decay.