Measurement of 3D Flow Structures of Turbulent Mixed Convection in a Rectangular Sample during Reconfiguration Events

Abstract

The flow in a mixed convection system is investigated in order to bridge the gap between fundamental Rayleigh- Bénard convection and the ventilation of passenger cabins. Our previous studies have revealed flow reconfigurations in certain parameter ranges. Yet the causing mechanism and the three-dimensional reconfiguration process of these events are still unknown. Therefore, we applied tomographic Particle Image Velocimetry (PIV) with helium-filled soap bubbles illuminated by an LED array to resolve secondary flow structures and to clarify whether the convection roll propagates in longitudinal direction during reconfiguration events. To capture these events the PIV acquisition was started after fulfilling a temperature condition. At the conference we will discuss the time development of the roll’s alignment as well as the interaction of the primary roll with secondary structures over the course of a reconfiguration.