DOI: 10.1615/ICHMT.2015.THMT-15
ISBN Print: 978-1-56700-427-4
ISBN CD: 978-1-56700-428-8
Two quasi-steady states observation in an asymmetrically heated vertical channel
ABSTRACT
Photovoltaic double-skin fac¸ades can be modelled by considering natural convection in an open-ended vertical channel heated under isoflux conditions. Such a system is particularly challenging for numerical simulations, where turbulence may be observed for high Rayleigh numbers (Ra* > 105, Ra* being the modified Rayleigh number based on channel width, aspect ratio, and wall heat flux). We present an experimental investigation of the flow along an asymmetrically-heated vertical channel with a modified Rayleigh of Ra* = 3.3 × 107. The flow behaviour is studied through direct measurements of velocities and temperatures in the channel. The main result is the observation of two quasi-steady states that occur successively without any influence on the flow. The states are said to be quasi-steady as their durations being much longer than the time needed to switch. The shift between these states may correspond to the existence of flow reversals.