Author(s)

C.T. Nguyen, S.E.B. Maïga, T. Maré & N. Galanis

Abstract

The problem of the transient laminar mixed convection flow in a vertical tube subject to time-dependent inlet boundary conditions has been numerically investigated. Results have clearly shown that successive step changes of the fluid inlet temperature have tremendous effects on the flow structure and its transient behaviors. It has been observed that a multiple-cell structure may co-exist in the tube. Thus, as hot fluid is cooled by heat loss to ambient environment, a first recirculation cell is noticed on the tube wall; it continues to increase both in volume and intensity. Shortly after the beginning of the positive step change of fluid inlet temperature, a second recirculatio

Keywords