Abstract
In the previous paper, the authors reported on the behavior of the thermally stratified layer under belt-driven circulation in the top layer of rectangular water tanks, and showed that the descent velocity of the stratified layer was determined by the densimetric Froude number. This paper clarifies the behavior of the stratified layer under wind-induced circulation in the top layer of a rectangular water tank. Wind-induced circulation has three main features; the first is that the water surface stagnates near the leeward wall of the water tank and the water surface is not driven uniformly; the second is that the densimetric Froude number increases with time owing to the heat loss from the water surface; the third is that the descent velocity of the stratified layer was not constant during the experiments but increases with time. However, the flow in the rectangular water tank is similar to that of the belt-driven circulation reported in the previous paper. It is clear that the descent velocity of the thermally stratified layer is determined by the densimetric Froude number and that the relation between the descent velocity and densimetric Froude number is expressed by an equation similar to that of belt-driven circulation. Prediction of the top layer temperature and the depth of the stratified layer was also tried with a simple model for the heat budget of the top layer and the equation for the descent velocity of the stratified layer. The predicted values agreed well with the experimental values.
