Model Experiment of Flow and Temperature Field around Urban Rivers

Abstract

The cooling effect of rivers was studied in terms of model experiments in which convective heat transfer and fluid velocity were measured for water flow in an open channel. The governing equations indicate that such a phenomenon depends on the Rayleigh number. It is observed that for small Rayleigh number, the flow consists of several longitudinal cells with a dimension of flow depth and weak large scale convective circulations with a scale of channel width. For large Rayleigh number, however, the latter circulation becomes predominant and the velocity on the non-heated area is remarkably large. It was observed that the cooling effect of non-heated area on heated area is limited to a narrow region, which agrees qualitatively with field observations.