Transient natural convection flow dynamics in a asymmetrically heated vertical channel

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.An experimental study in an open-ended vertical channel is carried out in order to describe the fluid dynamics during the early stage regime of free convection inside a vertical channel asymmetrically heated at uniform heat flux. The flow dynamics were characterized both by means of flow visualization techniques based on laser tomography and by velocity field measurements in the plane of symmetry of the channel using 2D-PIV (Particle Image Velocimetry) technique. The analysis allowed to detect a complex topological behaviour in the internal flow leading to numerous instabilities whose topological features are described. Vortex formation and shedding, vortex splitting, separation and beating of the boundary layer from one wall to another are identified, leading to an imbalance in the outlet pressure field which is certainly at the origin of a large-scale reversal flow.