Abstract
Transient natural convection along a vertical flat plate was investigated experimentally. To find out the fundamental characteristic of the transient region, wall temperature patterns on the heated wall were visualized using liquid crystal sheet and were analized by image processing. It is revealed from the visualization that the horseshoe-shaped low temperature pattern generated by the streamwise vortex appears on the wall and that it plays a significant role in heat transfer. The spanwise length and the life time of the horseshoe-shaped pattern can be estimated using buoyant parameters, such as (κν2/g β qw) 0.25 and (κ /g β qw) 0.5, which are the characteristic length scale and the characteristic time scale in transient natural convection.
