Abstract
Thermal fluctuation phenomenon is often observed in a enclosed cavity where hot and cold walls are located in a line, and causes a periodical location exchange of hot and cold flow cells. Since it only exists in limited area of some Rayleigh numbers, it is not easy to clarify the fluctuation mechanism and detailed characteristics of its heat transfer effect. This study tried to find the conditions for the occurrence of the fluctuation with experiments and then to analyze the mechanism numerically. As the results, thermal fluctuation phenomenon appeared in the range of inclined angle, 45°〜150° and most typical fluctuation existed at the inclined angle of 90° and in Raleigh numbers of (1〜7)×10^5. And the frequency of fluctuation tended to be divided into two area to each inclined angle of the cavity.
