Turbulent Natural Convection in a Horizontal Water Layer at High Rayleigh Numbers
高レイリー数域における水平流体層の乱流自然対流

Akira SAITO, Tetsuya SUMIDA, Sotoji ODAKE, Hiroshi SORA
2008 TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B  
The fluid flow and heat transfer of the turbulent natural convection in a horizontal water layer , with heated from below, were investigated experimentally . The experiment was performed for the Rayleigh number Ra in the range of 1.5×10 5 up to 3.9×10 10. As Ra increases above10 7, the circulating large-scale flow was gradually replaced by isolated rising and sinking plumes and then heat transfer was controlled by only those plumes. At Ra >109 , a three-dimensional vortex in addition to those
more » ... addition to those plumes was released from the thermal boundary layer. Consequently, this vortex appeared at high Rayleigh numbers seems to enhance the heat transfer process . For high Rayleigh numbers, the correlation between Ra and Nu is as follows : Nu=0.0930 Ra 0.326 (1.5×10 5<Ra<3.9 ×10 10).
doi:10.1299/kikaib.74.423 fatcat:dc47f4g6s5gcnkw5k2phpps72m