Thermal-hydraulic characteristics of stratified shear flow in braided rivers

Abstract

ABSTRACTComplex thermal-hydraulic phenomena associated with stratified shear flows in braided rivers have not yet been characterized. This paper fills this knowledge gap and reports extensive laboratory studies of both isothermal flow and thermal stratified flow with different velocity ratios between two layers. Results show that the high temperature zone shifted from the outer bank to the inner bank along an anabranch, but was reversed in the high-velocity zone. It is found that circulation cell structures, cross-sectional velocity distributions, shapes of separation zones, and locations of strong turbulent intensity in thermally stratified flow change with the velocity ratio. A comparative analysis of thermal stratified flow with isothermal flow is given. In particular, it is shown that the main lateral circulation cell was reversed in the thermal stratified flow compared with that in the isothermal flow.